How do you even get the compartment open that has the cd changer in it?

Since this is an high end AMG, I would go to Mercedes, these are very intricate cars, including the stereo systems, so have someone who is trained by Mercedes, deal with it. You may have a broken CD door lock etc.

Basically you cant without removal of the entire CD player and then disassembling the unit outside the vehicle. I first removed the compartment collar around the CD changer and then I went in and removed as much of the faceplate as I could and then really hacked at the magazine until I broke off the offending tray that was stuck in CD player. I destroyed the magazine but I got my CD's back out. I havent used it since and don't want to. I have a motorocker interface for my apple 4.