We've all heard that before. How do you come up with the conclusion that the funds are of unknown origin?
It must have come somewhere of course. I don't think OP will be interrogated and will be asked to send proof.
Unknown exchange suddenly got $210,000, getting them back is a long shot.
I have known that exchange for a long time and I have traded there for around $ 500. There is no problem at all in withdrawals or deposits, but for a fund of $ 210,000 they might suspect they are afraid of money laundering.