Couple different directions here - as well as variables (you many want to PM or email me at [email protected] for more details). Things to look at...
- if power shuts off completely, connection somewhere including battery
- if still showing throttle response on switch, but no motor power = sensor related -- sensor wire, motor sensor, sensor connection on VTX
- If error lights - which ones - alternating F and R would be a short somewhere in the motor, battery or connections

In this type of case - first thing I would do it little go back to step one. Take it out and re-trace any connections, plugs, wires, just like it was new to see if something is not right. Best case we find the issue, worse case - we look at warranty options.