Jg airsoft M4 shooting issue?

I recently bought a JG Airsoft M4 S-System Full Metal Gearbox AEG Rifle from airsoft megastore.com. I Charged the rifle having high hopes since it had good reviews. But about a few shots in it wolnt fire anymore. The battery is fully charged and the gun isnt jammed. Does anybody have any ideas on what could be wrong with it.