I feel the contractions on one side but not the other. What should I do?

Try the following steps:

1. If the signal is weaker on one side of the body, simply increase the intensity using the button on that side to make the exercise more energetic.
2. Stop the exercise, power off the controller, unfasten the Bottom Toner and make sure all of the gel pads on the side without signal are covering the metal studs completely.  Also, ensure that the gel pads are in good contact with your skin.  Reposition, if required, re-fasten the Bottom Toner and start training again.