How can I get the CD out of the CD Player?

The CD will not come out of the players plus the Radio will not play with this CD. It is Mazda 626 2001 CD players is MAZDA / FMS 4160 FMS. Cd players was working just fine my son change CD and now it won't work. I don't know if he put it in upside down or not but shouldn't it still come back out.