What if someone mistakenly sent you $6k to your wallet in exchange? You know their contact info but is a stranger. What would you do?

Imagine if somebody sent $6k USDT to your crypto wallet in exchange wallet (binance,coinbase, bitget, etc.) Somehow that person know that he sent you. He has your contact information and is trying to reach to you in DM for return. You also acknowledge that the funds are mistakenly sent by him.

What would be your course of action in this situation? How would you respond to this stranger's plea? What steps would you take to ensure the rightful return of the funds while also safeguarding your own interests and security in this unfamiliar interaction?