If the deposit is paid by credit card, the credit card receipt will state "PREAUTH" (pre-authorized amount). This corresponds to a direct debit authorization.
These amounts are usually released immediately after the rental agreement ends. However, in some countries (e.g., Greece), the average release takes 1-3 weeks. If you have any further questions about this after your vacation, please feel free to contact your DERTOUR Group tour representative by email.