Hi there - being a lawyer specializing in health issues, I have to say - if you need money for anything, you have it right now. That rehab clinic just committed massive malpractice and violated its state licence to practice by having faulty equipment... and for patients in chronic pain?! Of course they didn't file an incident report - it will be shut down immediately, fined by the state, and will owe you a pile of money! but don't you owe it to the other patients who will be injured by the careless maintenance of the equipment there to file a report?
You do not need to call that clinic back (obviously do not GO back - use your common sense!), but you should call the state's licensing board for health clinics or medical professionals. Usually it is part of the Department of Education, or Department of Health. If you tell me what state you are in, I will find it for you. You can file a complaint online.