What should I do if my customer's bank requires an IBAN but my instructions do not show one?

Do not turn an account number into an IBAN or add country letters to it. Use an IBAN only when it is supplied for that receiving account.

Ask the customer to check whether they chose the correct payment type and bank country. Some forms ask for different identifiers depending on whether the payment is local or international. Compare the selected form with the receiving instructions you shared.

If an IBAN is still mandatory, ask the payer's bank how to send to that account type, and contact Support with the required field and intended currency. Support can check the route. Do not use another currency's IBAN just to pass the form's validation.