What the???

I'd ethier tell 'em You broke it, you pay for it or, sure, no problem, put it on the bill. We'll square up at the finish. Then ask for the bill and deduct the difference with, "I'll see you in court if theres a problem." Now give me my car or I'll call the cops."

OR, pay the final installment via credit card and then call up the card company and cancell the whole thing. Or dedduct the windsheild amount.