I'd give the dealer one chance to get it right...then I'd call Mercedes' 800 number and complain. Of course, I'd let the dealer know that was my plan...
Sorry to hear of your troubles...been there, and been annoyed too!
"If everything seems under control, you're simply not going fast enough" --Mario Andretti
1995 E500 street car
1986 Porsche 944 Turbo S track car