[el ess A]

Problem is you signed for the work being completed and by doing so took the car as is. Likely you didn't inspect it before signing for it. Dealerships do this ALL the time. Here, sign this, now here's your keys. Only then do you get to see your car. Your car, you have a right to inspect before you sign it out into your responsibility.

Unfortunately, unless you can prove they did the damage, it's a he-said, she-said sort of situation since it has been a week.

Good luck anyway.