Removing the rear wheel, whether for repairs, replacing a tire or inner-tube, this needs to be handled correctly by someone with bike mechanic experience. 

When the rear wheel is removed, it can be detrimental to lay it flat on the axle where the motor cable is exiting as this can damage the cable and cause the motor to lose function completely which would not be covered under warranty.

When re-installing your rear wheel, make sure it is fully seated in the drop outs and stays in place as you tighten the axle nuts. This is critical for safety.

Once re-installed, please be sure to install a new zip-tie and verify your motor cable is routed properly to avoid damage or premature failure.

This video shows how to remove your rear wheel. Reference this video if you have questions about what steps need to be taken: