Mercedes Benz repair: Stereo Volume, 2007 mercedes clk, harman kardon

Question
I have a 2007 Mercedes CLK With a Harman Kardon stereo, the problem I'm having is the stereo volume tends to go up and down without touching anything. The car has been to the Mercedes dealership numerous times,they changed the amplifier, the antenna and the mic. Each time I pick up the car (after 3 or 4 days)they say they fixed the problem, by the time I get home I realize the problem is still there. PLEASE HELP

Answer
my best suggestion is try a different stereo and see if it does that with the new stereo seems like you have a malfunctioing amp. If the stealership said they replaced the stereo or any parts make damn sure you mark the parts prior to them changing them chances are they didnt change anything and you just paid for them to have your car sit there