Even if they broke it you are kind of up a creek without a paddle. If a person insists on taking a car to garages. Unless there is a real reason established to trust them . Always make a note of your odometer reading. Plus understand things are not under your control while they have your car.

In general the guys that worked on these models at mercedes dealerships have largely retired by now. The vast majority of mercedes dealers really know how to charge at the very high end for work as well.

Since the car was left there. I was also wondering if it was not locked up and perhaps someone forced the shift lever if the car sat outside overnight.

If so it may be just something like a bent or broken external part. There is also an outside possibility whatever is wrong was done on purpose to make money from you. They would have to be pretty crooked but that kind of senario is not totally unknown either.

You cannot accuse them of anything without some form of proof. This could have been circumstantial as well.