Refunds are issued onto the card they were taken from.
If your card has expired or been cancelled, then the transaction will be handled by your card issuer and automatically credited to your replacement card. If you don't have a replacement card, the your card issuer will try and deliver the refund using an alternate method (e.g. a bank account deposit). Failing that, it'll come back to us, but that would be rare!
If you have any concerns, don't hesitate to get in touch with the team on 0330 088 3838 or through our live chat.