Seat Belt Issue on 2001 Mercedes-Benz C320

My passenger seat belt will no longer work. It is locked in place and will not release. I received an estimate that is really unbelievable...$600.00. Is this a fair estimate?

Asked by for the 2001 Mercedes-Benz C320
Seat belts are always a dealer only item and with the liability attached to them are usually very expensive. Just put on on a newer Acura it was about that price for parts and labor.