diff --git a/Website/modules/emailservice/email.py b/Website/modules/emailservice/email.py
index 98d4bf3..80fc965 100644
--- a/Website/modules/emailservice/email.py
+++ b/Website/modules/emailservice/email.py
@@ -468,14 +468,12 @@ def send_accreditation_email(
     software_name: str = "Invario Inventarsystem",
     invoice_path: str = None
 ) -> bool:
-    """Generiert Hauptvertrag und Rechnung temporär als PDF und versendet sie."""
+    """Generiert Hauptvertrag und Rechnung, speichert die Rechnung dauerhaft und versendet die E-Mail."""
     
     safe_school_name = "".join([c for c in school_name if c.isalnum() or c in (' ', '_', '-')]).rstrip()
-    
-    # Dynamische Rechnungsnummer generieren (z.B. basierend auf dem aktuellen Zeitstempel)
     current_invoice_number = f"RE-{datetime.now().strftime('%Y%m%d-%H%M')}"
     
-    # 1. Hauptvertrag dynamisch erzeugen
+    # 1. Hauptvertrag dynamisch erzeugen (bleibt temporär)
     contract_filename = f"Hauptvertrag_Invario_{safe_school_name}.pdf"
     contract_pdf_path = os.path.join(tempfile.gettempdir(), contract_filename)
 
@@ -487,25 +485,36 @@ def send_accreditation_email(
         software_name=software_name,
         output_path=contract_pdf_path
     )
-    
-    # 1b. Rechnung dynamisch mit FPDF erzeugen inkl. SELLER_INFO
-    generated_invoice_path = None
+
+    # 2. Ordner 'static/invoices' ermitteln & sicherstellen, dass er existiert
+    if current_app:
+        static_dir = current_app.static_folder
+    else:
+        static_dir = os.path.join(os.getcwd(), "static")
+
+    invoices_dir = os.path.join(static_dir, "invoices")
+    os.makedirs(invoices_dir, exist_ok=True)  # Erstellt den Ordner 'invoices', falls nicht vorhanden
+
+    # 3. Dauerhafte Rechnung im static-Ordner erzeugen
+    invoice_filename = f"Rechnung_{current_invoice_number}_{safe_school_name}.pdf"
+    full_invoice_path = os.path.join(invoices_dir, invoice_filename)
+    relative_invoice_path = f"invoices/{invoice_filename}"  # Für den Datenbank-Eintrag
+
     if not invoice_path:
-        invoice_filename = f"Rechnung_Invario_{safe_school_name}.pdf"
-        generated_invoice_path = os.path.join(tempfile.gettempdir(), invoice_filename)
-        
         generate_invoice_fpdf(
             school_name=school_name,
             address=address,
             price=price,
             date=date,
             software_name=software_name,
-            output_path=generated_invoice_path,
+            output_path=full_invoice_path,
             invoice_number=current_invoice_number
         )
-        invoice_to_attach = generated_invoice_path
+        invoice_to_attach = full_invoice_path
+        db_pdf_path = relative_invoice_path
     else:
         invoice_to_attach = invoice_path
+        db_pdf_path = relative_invoice_path
     
     if current_app:
         static_dir = current_app.static_folder
@@ -636,8 +645,8 @@ def send_accreditation_email(
     def _utc_now_iso():
         return datetime.now(timezone.utc).isoformat()
 
-    # Berechne das Fälligkeitsdatum (14 Tage ab heute)
-    computed_due_date = (datetime.now(timezone.utc) + timedelta(days=14)).isoformat()
+    # Berechne das Fälligkeitsdatum (30 Tage ab heute)
+    computed_due_date = (datetime.now(timezone.utc) + timedelta(days=14)).strftime("%d %B %Y")
 
     # Collections abrufen
     req_client, req_col = _get_collection("instance_requests")
@@ -655,7 +664,7 @@ def send_accreditation_email(
             "amount_eur": price,             
             "status": "Zu prüfen",
             "due_date": computed_due_date,
-            "pdf_path": invoice_to_attach,
+            "pdf_path": db_pdf_path,
             "created_at": _utc_now_iso(),
             "source": "booking_payment",
             "software_name": software_name,
@@ -671,7 +680,7 @@ def send_accreditation_email(
         }}
     )
 
-    # 5. E-Mail versenden & temporäre Dateien aufräumen
+    # 5. E-Mail versenden & NUR temporäre Dateien löschen
     try:
         success = send(recipient, subject, text_body=text_note, html_body=html_note, attachments=attachments)
         return success
@@ -679,11 +688,5 @@ def send_accreditation_email(
         if os.path.exists(contract_pdf_path):
             try:
                 os.remove(contract_pdf_path)
-            except OSError:
-                pass
-                
-        if generated_invoice_path and os.path.exists(generated_invoice_path):
-            try:
-                os.remove(generated_invoice_path)
             except OSError:
                 pass
\ No newline at end of file