Follow the wires from the battery all the way to the motor. You should find a large amp sized fuse or a resettable circuit breaker in line. Razor PR200 24V Electric Motorbike Parts
You use the supplied charger, or if you got it used without a charger, you can buy one here: Replacement Razor Pocket Rocket PR200 Scooter Battery Charger Adapter... After that, you plug the charger into the wall securely, and pull down on the round cover next to the motorcycles power button until it opens. Then plug the other end of the charger into the motorcycle.
If it is a toy with multiple rechargable cells any one of the cells may be damaged and other cells may have no problem.
So just check wether all cells are ok or not.if not replace the damaged cell.
#1 check your power voltage on your batteries #2 you need to check the power to the electric motor - #3 possibly replace the control module - #4 possibly replace the throttle