Apple Watch Trade-in refused

I sent my old apple watch back with a promise of $90 off my current apple watch when I purchased it. The watch was returned under the claim that it did not match what I described. I disagree - it worked, it had no scratches or cracks, turned on and off, etc. There was no attempt to reconcile the issue, just a return and apple charged the $90 back to my account. It seems there should be a way to mediate the dispute - but apple it seems has given itself a kind of king-like control that is very unsettling. At least they have made it very difficult to contest a unilateral decision made by probably a single person. Anyway, I think I fairly judged the condition and apple should have accepted my trade.