I would go to another therapist and immediately tell them what has happened. It sounds to me like he is being manipulative to the point of not caring about you but only wanting you not to report him/the practice (hence the 3 other "henchmen" with him). Go to another professional and get help with what steps to take; the whole practice sounds rotten. It sounds like the others know and are closing ranks rather than throwing him out. Don't just "go away" (which would be fine with him too).

"Sorry" doesn't cut it! It is an abuse potentially as bad as a rape!