Recently my cd player that came with my volvo 850 has been malfunctioning where every so often it will have trouble reading a burned cd or the cartridge will pop out and i have to jam something in the crack of the door to push it back in. However, now on the audio system screen it says E as if the cartridges are empty, but i have 6 cds in there, one still in the actual player. The eject button is not working and i can't get the cartridge out, but the door does open. How can i fix this problem? To take it to the dealership would probably be extremely overpriced.