Takuma foil not working, where to start

Hi guys

I was given a Takuma efoil recently for free, it has a few issues and I was wondering if anyone had any ideas of how to get it up and running?

The main issue seems to be that im unable to connect the remote control to the ESC. It just says pairing on the remote and doesnt connect. This is a new remote (I didnt purchase), but it still wont connect. Could this mean it is an ESC issue?

I want to keep costs low on this project, so was wondering if it might be possible to fit a third party remote to the existing set up? Could I fit a fixed wire remote to bypass the remote receiver issue? I read somewhere about using a servo tester to test if the motor still runs through the ESC without the remote control?

Ive taken a look inside the ESC itself and everything looks fine in there, no damage etc.

I am very new to electronics so am not really sure what my options are. Any ideas would be greatly appreciated.