Contact support, it’s a scam. You could still get burned if you don’t contact support.

I had a similar thing happen on PayPal. I didn’t send the refund and then PayPal support got confused because the person claimed they bought something off me and I failed to ship it.

So PayPal reversed everything, but then charged me a “dispute fee” since I filed a case and they found in the other party’s favor.

I at least did not end up losing the money. I just had to pay a fee.