Recently, I sold cryptocurrency to someone in Australia via a bank transfer. I had him transfer the money from his bank to my TransferWise (Wise) AUD account. A few hours ago, I got an email from Wise saying the sender's bank wants the money back, but Wise is giving me the option to deny refunds. What should I do in this situation? I already gave him the cryptocurrency, so I obviously will be losing money if I agree to the refund. However, I don't want to get into lawsuits either. Thanks a lot.
EDIT 1 Responding to the answer and comments, I have a few more details to add. The buyer, Andrew (I will omit his last name), has completed KYC verification on the platform that we were trading. Also, he sent money from an account in his name, and he provided the payment receipt, so it's implausible that this payment was unauthorized.