First time posting.

I have a Radrunner 2 purchased in 2021.  I have no power from my motor and the rear tire will not spin backwards.  The bike has a new controller from Rad and that works fine.  Tested it on other Radrunner 2. 
I live in Key West and I'm guessing between the salty air, heavy rain, and sometimes slightly flooded streets, the motor is seized up.  I'm looking for a replacement without much luck. 
Any suggestions on where I can find a replacement?  Area 13 says their 750 Bafang is not compatible.

Thanks for any help!