Just having personal 'accountability' is not enough. Consequences are powerful motivators. Other consequences that have worked... $50 donations to a non-profit that the individual dislikes greatly.
I will add this personal anecdote. These goals calls have often been the only reason I got difficult things done. Like going back to the gym, eating well, consistently exercising. It is all too easy to procrastinate.
Your program could be beneficial to so many, to improve their lives. Coaching at a discounted, mass-scale would be amazing!