Broken AEG Airsoft gun, how do i fix it?

during a match, the gun slowed down like the battery was dieing but now it wont hold a charge, and the trigger may be jammed

its an M16 but im not really shure on the brand

same thing happened with me. you overcharged your battery b/c you don't have a smart charger. get a new battery and you'll be as good as new.
thx for the help :)