How do I change the motor?

I had an issue with my boosted board as I was riding, the left back motor suddenly overheated and just stopped turning , I let it cool down but when I try to accelerate (even when Im not on it) the left wheel turns very slowly as if there is friction stopping it from turning.

I contacted boosted but they required shipping the board to the US (I dont live in the US and shipping to the US is very expensive where I am from)

Any tips would highly be appreciated.