diff --git a/app/Domains/Invoice/Actions/ChangeStatus/ChangeStatusCommand.php b/app/Domains/Invoice/Actions/ChangeStatus/ChangeStatusCommand.php
index 01848b0..d7f59b7 100644
--- a/app/Domains/Invoice/Actions/ChangeStatus/ChangeStatusCommand.php
+++ b/app/Domains/Invoice/Actions/ChangeStatus/ChangeStatusCommand.php
@@ -3,6 +3,11 @@
 namespace App\Domains\Invoice\Actions\ChangeStatus;
 
 use App\Enumerations\InvoiceStatus;
+use App\Mail\InvoiceMails\InvoiceMailsApprovedInvoiceMail;
+use App\Mail\InvoiceMails\InvoiceMailsDeniedInvoiceMail;
+use App\Mail\InvoiceMails\InvoiceMailsReopenedInvoiceMail;
+use App\Mail\ParticipantCocMails\ParticipantCocCompleteMail;
+use Illuminate\Support\Facades\Mail;
 
 class ChangeStatusCommand {
     private ChangeStatusRequest $request;
@@ -19,6 +24,13 @@ class ChangeStatusCommand {
                 $this->request->invoice->status = InvoiceStatus::INVOICE_STATUS_APPROVED;
                 $this->request->invoice->approved_by = auth()->user()->id;
                 $this->request->invoice->approved_at = now();
+
+                if ($this->request->invoice->contact_email !== null) {
+                    Mail::to($this->request->invoice->contact_email)->send(new InvoiceMailsApprovedInvoiceMail(
+                        invoice: $this->request->invoice,
+                        costUnit: $this->request->invoice->costUnit()->first(),
+                    ));
+                }
                 break;
 
             case InvoiceStatus::INVOICE_STATUS_DENIED:
@@ -26,6 +38,12 @@ class ChangeStatusCommand {
                 $this->request->invoice->denied_by = auth()->user()->id;
                 $this->request->invoice->denied_at = now();
                 $this->request->invoice->denied_reason = $this->request->comment;
+                if ($this->request->invoice->contact_email !== null) {
+                    Mail::to($this->request->invoice->contact_email)->send(new InvoiceMailsDeniedInvoiceMail(
+                        invoice: $this->request->invoice,
+                        costUnit: $this->request->invoice->costUnit()->first(),
+                    ));
+                }
                 break;
             case InvoiceStatus::INVOICE_STATUS_NEW:
                 $this->request->invoice->status = InvoiceStatus::INVOICE_STATUS_NEW;
@@ -35,6 +53,12 @@ class ChangeStatusCommand {
                 $this->request->invoice->denied_at = null;
                 $this->request->invoice->comment = $this->request->invoice->denied_reason;
                 $this->request->invoice->denied_reason = null;
+                if ($this->request->invoice->contact_email !== null) {
+                    Mail::to($this->request->invoice->contact_email)->send(new InvoiceMailsReopenedInvoiceMail(
+                        invoice: $this->request->invoice,
+                        costUnit: $this->request->invoice->costUnit()->first(),
+                    ));
+                }
                 break;
             case InvoiceStatus::INVOICE_STATUS_DELETED:
                 $this->request->invoice->status = InvoiceStatus::INVOICE_STATUS_DELETED;
@@ -49,7 +73,6 @@ class ChangeStatusCommand {
             $response->success = true;
         }
 
-
         return $response;
     }
 }
diff --git a/app/Domains/Invoice/Views/Partials/invoiceDetails/InvoiceDetails.vue b/app/Domains/Invoice/Views/Partials/invoiceDetails/InvoiceDetails.vue
index 29fc008..4573d6c 100644
--- a/app/Domains/Invoice/Views/Partials/invoiceDetails/InvoiceDetails.vue
+++ b/app/Domains/Invoice/Views/Partials/invoiceDetails/InvoiceDetails.vue
@@ -177,7 +177,7 @@ async function reopenInvoice() {
   <Modal title="Abrechnung ablehnen" :show="denyInvoiceDialog" @close="denyInvoiceDialog = false" >
     Begründung:
     <textarea class="mareike-textarea" style="width: 100%; height: 100px; margin-top: 10px;" id="deny_invoice_reason" />
-    <input type="button" class="mareike-button mareike-deny-invoice-button" value="Abrechnung ablehnen" @click="denyInvoice" />
+    <input type="button" class="mareike-button mareike-deny-invoice-button" style="width: 250px !important;" value="Abrechnung ablehnen" @click="denyInvoice" />
   </Modal>
 
 </template>
diff --git a/app/Domains/Invoice/Views/Partials/newInvoice/refund-data.vue b/app/Domains/Invoice/Views/Partials/newInvoice/refund-data.vue
index c48da1c..4010728 100644
--- a/app/Domains/Invoice/Views/Partials/newInvoice/refund-data.vue
+++ b/app/Domains/Invoice/Views/Partials/newInvoice/refund-data.vue
@@ -102,25 +102,27 @@ async function sendData() {
             name="contact_name" v-model="userName"
             style="font-size: 14pt; width: 550px;" /><br /><br />
 
-        <label>
+        <label v-if="userName !== ''">
             <strong>E-Mail-Adresse (Für Rückfragen):</strong>
         </label><br />
         <input
+            v-if="userName !== ''"
             type="email"
             name="contact_email"
             v-model="userEmail"
             style="font-size: 14pt; width: 550px;" /><br /><br />
 
-        <label>
+        <label v-if="userName !== ''">
             <strong>Telefonnummer (für Rückfragen):</strong>
         </label><br />
         <input
+            v-if="userName !== ''"
             type="text"
             id="contact_telephone"
             name="contact_telephone" v-model="userTelephone"
             style="font-size: 14pt; width: 550px;" /><br /><br />
 
-        <span id="decision" v-if="userName !== '' && decision === ''">
+        <span id="decision" v-if="userEmail !== '' && decision === ''">
           <label><br />
               <strong>Möchtest du den Betrag spenden?</strong>
           </label><br />
diff --git a/app/Mail/InvoiceMails/InvoiceMailsApprovedInvoiceMail.php b/app/Mail/InvoiceMails/InvoiceMailsApprovedInvoiceMail.php
new file mode 100644
index 0000000..6a0c506
--- /dev/null
+++ b/app/Mail/InvoiceMails/InvoiceMailsApprovedInvoiceMail.php
@@ -0,0 +1,79 @@
+<?php
+
+namespace App\Mail\InvoiceMails;
+
+use App\Enumerations\InvoiceStatus;
+use App\Enumerations\InvoiceType;
+use App\Models\CostUnit;
+use App\Models\Invoice;
+use App\Resources\CostUnitResource;
+use App\Resources\InvoiceResource;
+use App\ValueObjects\Amount;
+use Illuminate\Http\Request;
+use Illuminate\Mail\Mailable;
+use Illuminate\Mail\Mailables\Attachment;
+use Illuminate\Mail\Mailables\Content;
+use Illuminate\Mail\Mailables\Envelope;
+
+class InvoiceMailsApprovedInvoiceMail extends Mailable {
+    public function __construct(
+        private Invoice $invoice,
+        private CostUnit $costUnit,
+    )
+    {
+        //
+    }
+
+    /**
+     * Get the message envelope.
+     */
+    public function envelope(): Envelope
+    {
+        return new Envelope(
+            subject: 'Deine Abrechnung wurde zur Auszahlung freigegeben',
+        );
+    }
+
+    /**
+     * Get the message content definition.
+     */
+    public function content(): Content
+    {
+        $costUnit = new CostUnitResource($this->costUnit)->toArray(new Request());
+        $invoice = new InvoiceResource($this->invoice)->toArray(new Request());
+
+        $invoiceStatus = match($invoice['status']) {
+            InvoiceStatus::INVOICE_STATUS_APPROVED => 'Zur Auszahlung freigegeben',
+            InvoiceStatus::INVOICE_STATUS_DENIED => 'Nicht auszahlbar und zurückgewiesen',
+            InvoiceStatus::INVOICE_STATUS_NEW => 'Erneut zur Prüfung geöffnet',
+            default => 'Unbekannt',
+        };
+
+        $invoiceType = match($invoice['internalType']) {
+            InvoiceType::INVOICE_TYPE_TRAVELLING => sprintf( 'Reisekosten [%1$s]', $invoice['travelReason']),
+            default => $invoice['invoiceType'],
+        };
+
+        return new Content(
+            view: 'emails.invoices.changed_invoice_state',
+            with: [
+                'costUnitContactMail' => $this->costUnit->tenant()->first()->email_finance,
+                'invoiceStatus' => $invoiceStatus,
+                'costUnit' => $costUnit,
+                'invoice' => $invoice,
+                'invoiceType' => $invoiceType,
+            ],
+        );
+    }
+
+
+    /**
+     * Get the attachments for the message.
+     *
+     * @return array<int, Attachment>
+     */
+    public function attachments(): array
+    {
+        return [];
+    }
+}
diff --git a/app/Mail/InvoiceMails/InvoiceMailsDeniedInvoiceMail.php b/app/Mail/InvoiceMails/InvoiceMailsDeniedInvoiceMail.php
new file mode 100644
index 0000000..48db841
--- /dev/null
+++ b/app/Mail/InvoiceMails/InvoiceMailsDeniedInvoiceMail.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace App\Mail\InvoiceMails;
+
+use App\Enumerations\InvoiceStatus;
+use App\Enumerations\InvoiceType;
+use App\Models\CostUnit;
+use App\Models\Event;
+use App\Models\EventParticipant;
+use App\Models\Invoice;
+use App\Resources\CostUnitResource;
+use App\Resources\InvoiceResource;
+use App\ValueObjects\Amount;
+use Illuminate\Http\Request;
+use Illuminate\Mail\Mailable;
+use Illuminate\Mail\Mailables\Attachment;
+use Illuminate\Mail\Mailables\Content;
+use Illuminate\Mail\Mailables\Envelope;
+
+class InvoiceMailsDeniedInvoiceMail extends Mailable {
+    public function __construct(
+        private Invoice $invoice,
+        private CostUnit $costUnit,
+    )
+    {
+        //
+    }
+
+    /**
+     * Get the message envelope.
+     */
+    public function envelope(): Envelope
+    {
+        return new Envelope(
+            subject: 'Deine Abrechnung wurde zurückgewiesen',
+        );
+    }
+
+    /**
+     * Get the message content definition.
+     */
+    public function content(): Content
+    {
+        $costUnit = new CostUnitResource($this->costUnit)->toArray(new Request());
+        $invoice = new InvoiceResource($this->invoice)->toArray(new Request());
+
+        $invoiceStatus = match($invoice['status']) {
+            InvoiceStatus::INVOICE_STATUS_APPROVED => 'Zur Auszahlung freigegeben',
+            InvoiceStatus::INVOICE_STATUS_DENIED => 'Nicht auszahlbar und zurückgewiesen',
+            InvoiceStatus::INVOICE_STATUS_NEW => 'Erneut zur Prüfung geöffnet',
+            default => 'Unbekannt',
+        };
+
+        $invoiceType = match($invoice['internalType']) {
+            InvoiceType::INVOICE_TYPE_TRAVELLING => sprintf( 'Reisekosten [%1$s]', $invoice['travelReason']),
+            default => $invoice['invoiceType'],
+        };
+
+        return new Content(
+            view: 'emails.invoices.changed_invoice_state',
+            with: [
+                'costUnitContactMail' => $this->costUnit->tenant()->first()->email_finance,
+                'invoiceStatus' => $invoiceStatus,
+                'costUnit' => $costUnit,
+                'invoice' => $invoice,
+                'invoiceType' => $invoiceType,
+            ],
+        );
+    }
+
+
+    /**
+     * Get the attachments for the message.
+     *
+     * @return array<int, Attachment>
+     */
+    public function attachments(): array
+    {
+        return [];
+    }
+}
diff --git a/app/Mail/InvoiceMails/InvoiceMailsReopenedInvoiceMail.php b/app/Mail/InvoiceMails/InvoiceMailsReopenedInvoiceMail.php
new file mode 100644
index 0000000..4f75d0a
--- /dev/null
+++ b/app/Mail/InvoiceMails/InvoiceMailsReopenedInvoiceMail.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace App\Mail\InvoiceMails;
+
+use App\Enumerations\InvoiceStatus;
+use App\Enumerations\InvoiceType;
+use App\Models\CostUnit;
+use App\Models\Event;
+use App\Models\EventParticipant;
+use App\Models\Invoice;
+use App\Resources\CostUnitResource;
+use App\Resources\InvoiceResource;
+use App\ValueObjects\Amount;
+use Illuminate\Http\Request;
+use Illuminate\Mail\Mailable;
+use Illuminate\Mail\Mailables\Attachment;
+use Illuminate\Mail\Mailables\Content;
+use Illuminate\Mail\Mailables\Envelope;
+
+class InvoiceMailsReopenedInvoiceMail extends Mailable {
+    public function __construct(
+        private Invoice $invoice,
+        private CostUnit $costUnit,
+    )
+    {
+        //
+    }
+
+    /**
+     * Get the message envelope.
+     */
+    public function envelope(): Envelope
+    {
+        return new Envelope(
+            subject: 'Deine Abrechnung wird erneut geprüft',
+        );
+    }
+
+    /**
+     * Get the message content definition.
+     */
+    public function content(): Content
+    {
+        $costUnit = new CostUnitResource($this->costUnit)->toArray(new Request());
+        $invoice = new InvoiceResource($this->invoice)->toArray(new Request());
+
+        $invoiceStatus = match($invoice['status']) {
+            InvoiceStatus::INVOICE_STATUS_APPROVED => 'Zur Auszahlung freigegeben',
+            InvoiceStatus::INVOICE_STATUS_DENIED => 'Nicht auszahlbar und zurückgewiesen',
+            InvoiceStatus::INVOICE_STATUS_NEW => 'Erneut zur Prüfung geöffnet',
+            default => 'Unbekannt',
+        };
+
+        $invoiceType = match($invoice['internalType']) {
+            InvoiceType::INVOICE_TYPE_TRAVELLING => sprintf( 'Reisekosten [%1$s]', $invoice['travelReason']),
+            default => $invoice['invoiceType'],
+        };
+
+        return new Content(
+            view: 'emails.invoices.changed_invoice_state',
+            with: [
+                'costUnitContactMail' => $this->costUnit->tenant()->first()->email_finance,
+                'invoiceStatus' => $invoiceStatus,
+                'costUnit' => $costUnit,
+                'invoice' => $invoice,
+                'invoiceType' => $invoiceType,
+            ],
+        );
+    }
+
+
+    /**
+     * Get the attachments for the message.
+     *
+     * @return array<int, Attachment>
+     */
+    public function attachments(): array
+    {
+        return [];
+    }
+}
diff --git a/app/Models/CostUnit.php b/app/Models/CostUnit.php
index c8332f3..afb66e3 100644
--- a/app/Models/CostUnit.php
+++ b/app/Models/CostUnit.php
@@ -3,6 +3,7 @@
 namespace App\Models;
 
 use App\Scopes\InstancedModel;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 
@@ -42,4 +43,8 @@ class CostUnit extends InstancedModel
     public function invoices() : hasMany {
         return $this->hasMany(Invoice::class);
     }
+
+    public function tenant() : BelongsTo {
+        return $this->belongsTo(Tenant::class, 'tenant', 'slug');
+    }
 }
diff --git a/app/Resources/InvoiceResource.php b/app/Resources/InvoiceResource.php
index f26fb74..478a40f 100644
--- a/app/Resources/InvoiceResource.php
+++ b/app/Resources/InvoiceResource.php
@@ -49,7 +49,7 @@ class InvoiceResource {
         $returnData['deniedReason'] = $this->invoice->denied_reason ?? '--';
         $returnData['travelDirection'] = $this->invoice->travel_direction ?? '--';
         $returnData['travelReason'] = $this->invoice->travel_reason ?? '--';
-        $returnData['distance'] = $this->invoice->distance;
+        $returnData['distance'] = $this->invoice->distance ?? '--';
         $returnData['distanceAllowance'] = new Amount($this->invoice->costUnit()->first()->distance_allowance, '')->toString();
         $returnData['passengers'] = $this->invoice->passengers ? 'Ja' : 'Nein';
         $returnData['transportation'] = $this->invoice->transportation ? 'Ja' : 'Nein';
diff --git a/resources/views/emails/invoices/changed_invoice_state.blade.php b/resources/views/emails/invoices/changed_invoice_state.blade.php
new file mode 100644
index 0000000..3cf2f32
--- /dev/null
+++ b/resources/views/emails/invoices/changed_invoice_state.blade.php
@@ -0,0 +1,90 @@
+<!DOCTYPE html>
+<html>
+<body>
+<h1>Hallo {{$invoice['contactName']}},</h1>
+<p>
+    soeben wurde eine Abrechnung, die eingereicht hast, bearbeitet.<br />
+    In der nachfolgenden Übersicht findest du weitere Details zu der Abrechnung:
+</p>
+
+
+<table cellpadding="0" cellspacing="0" border="0"
+       style="width: 100%; max-width: 640px; border-collapse: collapse; font-family: Arial, sans-serif; font-size: 14px; color: #1f2937;">
+
+    <tr>
+        <td style="padding: 8px 12px; width: 180px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+            Veranstaltung / Kostenstelle:
+        </td>
+        <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+            {{$costUnit['name']}}
+        </td>
+    </tr>
+
+    <tr>
+        <td style="padding: 8px 12px; width: 180px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+            Betrag:
+        </td>
+        <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+            {{$invoice['amount']}}
+        </td>
+    </tr>
+
+    <tr>
+        <td style="padding: 8px 12px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+            Grund der Abrechnung:
+        </td>
+        <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+            {{$invoiceType}}
+        </td>
+    </tr>
+
+    @if($invoice['travelDirection'] !== '--')
+        <tr>
+            <td style="padding: 8px 12px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+                Reiseweg:
+            </td>
+            <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+                {{$invoice['travelDirection'] }}
+            </td>
+        </tr>
+    @endif
+
+    @if($invoice['distance'] !== '--')
+        <tr>
+            <td style="padding: 8px 12px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+                Entfernung:
+            </td>
+            <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+                {{$invoice['distance'] }} km
+            </td>
+        </tr>
+    @endif
+
+    <tr>
+        <td style="padding: 8px 12px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+            Neuer Status:
+        </td>
+        <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+            {{$invoiceStatus}}
+        </td>
+    </tr>
+
+    @if($invoice['deniedReason'] !== '--')
+        <tr>
+            <td style="padding: 8px 12px; font-weight: 600; color: #4b5563; border-bottom: 1px solid #e5e7eb;">
+                Begründung:
+            </td>
+            <td style="padding: 8px 12px; border-bottom: 1px solid #e5e7eb;">
+                {!! $invoice['deniedReason'] !!}
+            </td>
+        </tr>
+    @endif
+</table>
+
+
+<p>
+    Wenn du mit der Entscheidung nicht einverstanden bist, oder du Fragen zum weiteren Ablauf hast, kontaktiere bitte bitte die Aktionsleitung auf den bekannten Wegen oder gerne per E-Mail unter der Adresse:
+    {{$costUnitContactMail}}
+</p>
+</body>
+</html>