Multi disc CD changer, won't eject!!

My multi disc CD changer won't eject! It's a Navisys 6disc system with sat-nav. The 6disc changer is under the drivers seat. It was working, I changed the CD and it stopped, it now won't play and one of the middle discs is stuck.

Any help on a reset button or the like would be a great help!

Cheers, Mick.