If your current dealer won't take care of the problem take it to another dealer if one is near by. If you can't take it to another dealer request a meeting with the DC Zone Rep.

I feel your pain. When I owned a GM vehicle I could not take it into the dealer without having one issue or another with them. Got to the point where I just called GM's 800 number and they ensured the dealer did their job. PITA to have to do this every trip but better than multiple trips for the same problem.