Coming from another Buddhist, sometimes some people needs to be ajar kau kau so that he/she will not scam people in the future. Let a thief go easy, they become a robber. Not helping that person to change.

Perhaps you can explain to the bank and ask if the account number that was used to transfer the money to your account belongs to this Tan person.
If the staff is kind enough, at least can tell you YES or NO; that's all you need at the moment. If the answer is a NO, then just tell him Game's over.