Dealership refunded warranty, won't refund tax.

I'm a Michigan resident who purchased an used car in Ohio. I made the fatal mistake of financing with the dealer. They tacked on a warranty and overpriced GAP policy. I'm looking to refinance immediately and I cancelled both. Finally I managed to get them issue full refunds (almost 2 months of back and forth) however they are refusing to refund the 6% tax collected saying "they don't do that".

Ohio dealerships collect taxes for Michigan and it would only make sense they would refund the remainder of the tax.

We're talking about $200 so it's certainly not work me driving back to Ohio and sue them in small claims for it, I'm not sure if I even could.

Is there somebody I can try to talk to about it, or is there a way I can claim the overpayment on my Michigan return?