Mercedes Benz constantia damaged my car

Brought my car in for a small repair and I got it back with a scratch on my back bumper and top of the booth door. When I notified the dealership (Mercedes Constantia) not only they didn’t take responsibility despite the clear fact that this happened after the car was washed. The scratch paint is even still on the tire. Been waiting over an hour now as they review the footage. How long does it take to review a footage?it’s been over 1h30 mins. I am preparing for legal action and will mos def never bring my car at this dealership. After 2 years it is sad we have to part in this manner.