Legal Question in Credit and Debt Law in Missouri

Under the facts you described, the shop owes you for the fair market value of the ruined tires. If the tires wer older, they were not worth the cost of new relacements. The easiest way is the have the shop figure your bill, then you deduct the fair market value of the tires from what you pay. The value of used tires is hard to estimate. Therefore, you and the shop may need to confer and compromise. If you have already paid, then you may need to sue in small claims court to get reimbursed for the loss of the tires.

Good luck