I work for upmc in one of the depts that are involved in fixing this kinda thing. Not in the billing dept so I can’t really give any in depth advice but.. Definitely check identity theft. You’d be shocked at how often it happens. Also weird things happen when patients are registered on occasion it could be a genuine accident. They’ll work with you after they do some investigation on what went wrong. Just keep calling

Edit: call upmc patient relations if you need to get the ball rolling