Did some other modifications

app/database.py

@@ -641,5 +641,22 @@ def get_all_invoice_ids(raffle_id):
     except Exception as e:
         logger.error(f"Error getting invoice IDs for raffle {raffle_id}: {e}")
         return []
+    finally:
+        conn.close()
+
+def delete_reservation_timestamp(invoice_id):
+    """Clears the reservation_timestamp for a participant by invoice_id."""
+    conn = connect_db()
+    cur = conn.cursor()
+    try:
+        cur.execute(
+            "UPDATE participants SET reservation_timestamp=NULL WHERE invoice_id=? AND step='waiting_for_payment'",
+            (invoice_id,)
+        )
+        conn.commit()
+        logger.info(f"Cleared reservation_timestamp for invoice {invoice_id}")
+    except Exception as e:
+        logger.error(f"Error clearing reservation_timestamp for invoice {invoice_id}: {e}")
+        conn.rollback()
     finally:
         conn.close()