The payment system for refunds differs per bank.

Once the refund is finalised in your system, the amount is paid to the bank that issued the card. The time required before the refund is received, depends on the card holder's bank.

In My EMS you can see the status of the refund. Has the status been successful, but the amount has not yet been credited to your customer's account? Please indicate that your customer can dispute the refund through his/her bank.