Whats wrong with my 125B?

[Maxxman]

I've had it less than 6 months and had it working then. A battery shorted on the chassis while I was driving and ever since then it doesn't work.
I tried it again with a 8xl and it demagnitised it. Today, I tried it again and it just stutters like its fighting itself, on its own the motor spins freely and the controller got warm after about 20 seconds of this stuttering.

Is there anything I can do to solve it or should I send it back to S&T?

Any help would be great, thanks.