It can be semi-common with in dash CD changers, especially if you have any discs in it with adhesive labels. Also some changers dislike certain brands of CDs...... I think they're thicker or heavier or something.
In any case these changers jamming happens. If they don't come out with the battery trick you could either try disassembling the changer yourself, or if you're under warranty they'll generally replace the HU and send it off to get your CD's out. They'll mail them back to you but they could be awhile in coming.