I received btc before pay the saller. its seem to a bug

The system did not wait for me to do the bank transfer and has already released the btc to my account. That was awful. This can be used as scams. the referee may have gone wrong or the seller ok without checking the funds.

It’s hardly a scam. As a BTC buyer you’re very safe. The seller should only be able to release the funds to you after you’ve clicked that you’ve started the payment. Have you done so?

Any way, I imagine that you still have their bank account details to do the transfer. Do so. It may also be worth it to contact the Arbitrators directly for more guidance. Avoid sharing personal information publicly.