ML320 Radio Code

I can't get my Radio code to work. Mercedes dealer give me the code, but it doesn't like it. It keeps getting into a waiting mode. Dealer said that I need to pay $180 dollars to check. Any ideas?

You could have a different radio in there to the one it came from the factory with. First thing to try is take the set out, get the serial number off the side. MB dealers can get the radio code to that specific set from the serial number from the radio. If that doesn't work unplug it and reset the unit. Then try the code. If that doesn't work, get a new set!