The Merchant Back Office will allow you to check whether the buyer has been debited twice:

1. Sign in to the Merchant Back Office.
2. Go to the Management > Transactions menu.
3. Search for the transaction(s) using one of the following criteria:
   1. Amount
   2. Date
   3. Buyer’s e-mail (if available).

If only one transaction is visible in the Merchant Back Office, this means the payment was submitted to the bank only once. Therefore, the buyer should contact their bank to find out why they were charged twice.