Is this a factory 6 disk CD changer from Alpine? If so, just insert a credit card under your CD magazine. You will hear a click and the magazine will pop out.
When you remove your magazine and find a CD still in your changer, just remove all your CD from you magazine and put it back into your changer. The Cd will be put back into you Magazine the next time you take it out.
I had an E46 in the other day, same thing as yours....the fuse on the underside of the changer had blown. Replaced the fuse and everything worked normally again. I would check that first...hopefully something simple like that and not have to pay for a replacement!