Audio Systems: CD player stopped working after battery change, fist time, battery cables

Question
Hello, I have a 2006 Eddie Bauer Ltd Ford Explorer. Today the battery died and I had to have it replaced. Now my cd player won't work. It is one of the 6 cd changers which read the MP3 discs, and all the slots were loaded. The message says "no disk" when I try to play, "no disk" when I try to eject, and if i hit the load button it says "disk error" We have unhooked the battery cables a few times to try to reset but it did't help. The dealer wants me to bring it in for them to look at but since I just got charged over $200 to replace the battery, I'm a little reluctant to have them double charge me again. Any suggestions?

Answer
the radio needs to be repair,
if it loses power  the next time you power the radio it believes it is the fist time and moves from shipping mode to  empty location ready to takes disks, the problem is that it was full of discs,
so it move in the wrong direction and got stuck, the radio needs to be service
good luck