A refund usually takes up to 10 days before it reaches your customers’ account. You can always go to your acquirer dashboard and check the status of the refunded transaction. If it’s status code is 20000 (approved) the refund has been processed.
Very rarely a refund can take up to 30 days.
Tip: If a customer reaches out to you and asks if you’ve initiated the refund yet. You can provide superb customer service, by sending a screenshot of the status code, that it in fact has been initiated. On top of that, you can also send the customer the ARN for the transaction. They can then bring that to their bank, and the bank should be able to locate the refund and determine when the customer can expect the funds on their account.