A credit is complete bull, they need to pay to repair your wheels. They lied to you and messed up your car. I would advice you to force them to agree to pay the repair before you have it done. If you repair it then send them the bill, they can more easily deny you reimbursement. I had American Tire destroy one of my hubs and they were really nice about paying to replace it.

I would agree with having them agree to pay up front. The problem is that the owner still denies that his car wash track could have caused the damage, and claims that he must not have seen the scratches before the car went in. Its an unfortunate situation.