Wellif you are in Atlanta, You should look up Benzmac to work on your car.
I know I'd be usuing him if I live in Atlanta.
In anycase, we all feel your pain, Most dealerships, not only mercedes benz dealers, treat the customer poorly from my experience, not doing the job they were supposed to do.
I took my jeep to the dealer, told them the thermostat was bad, they did not change it. They told me the valve cover was leaking oil. I told them to fix it.
I got the car back, no fixed valve cover, no changed thermostat. What was the excuse of my service advisor? "I wasn't listening to you." He tells me. So I tookt he car to another dealer, told them what happened, and they did the work. Well my overheating problem was gone, and no more leak from the valve cover.
My father took his Mercedes to the Beverly Hills Dealer. They tell him it needs a new tranny. by this time they have had the car off and on for 4 weeks. They want a Ridiculous small fortune, coming to the price of a good used honda or toyota. He takes it to my independent, Car was fixed easily, for way less than what they were trying to charge him at the dealer, all on a car with 60k on the odo.
My brother took his car to the range rover dealer. They wanted to basically have him rebuild half the friggin drivetrain in the car. The car would not go anywhere forward or reverse, but the car engaged gear on the tranny. First they told him new tranny, then they told him new front and rear differential as well. To the tune of basically what he paid for the car used two years ago. The local independent he took the car to, found two problems, all it needed was a new axl in the rear, and new front driveshaft.
Not all dealerships provide this kind of service, but These kinds of stories are quite the norm. My friend's Tranny in his BMW went out. He got it rebuilt by the dealer with a 2 year 24k warranty. 30k later it went out again. He had the dealer rebuild it again, for the same price he paid the time before. The independent mech he now goes to, quoted him much much less to do it again if it happened again, and my friend now refuses to go to the dealer.
He doesn't even take his 2001 Toyota LandCruiser to the dealer, and its under warranty!!! He called toyota USA, told them he would never take it to the dealer for anything, And got them to approve his independent to do the warranty work on the car. His attorney can be very persuasive. All just so he would not have to deal with the dealerships.
I Personally would use the dealer if the car was under warranty. but if its not, Why would I want to waste the effort.