CHAT ROOM

My $0.02 worth...

The promoter should have paid you as you taught for him as agreed. He may argue that you didn't teach what he wanted you to, but from what happened your respective interpretations of what Intermediate apparently differs, at least with regard to that group of students. As he probably didn't give a specific syllabus for the class then he is trusting in your professional judgement. As he's unhappy with your judgement the simple answer is for him not to hire you again.

(Sadly the cost of taking legal action probably is more that your fee and even if you won there's no guarantee you would see your money. Is this a common problem?)

Unless it was possible to split the group into two levels, which is probably unlikely, you were absolutely correct to adjust what you taught to match the level of the class. Not doing so would have been demoralising to those not up to the level as they would have struggled, and potentially dangerous if not in class but on the dance-floor. Its easy to injure a woman through a poor lead and safety always has to be the number one priority.

One way to try and keep the higher-level students happy with the 'dumming down' of the routine you taught would be give them extras to do while executing the same routine; eg if doing a XBL to an open-hold you could have had the higher-level men doing a suzy-q shine while leading it with the lower-level men just doing the bog-standard footwork.

"Improver", "intermediate", etc are just labels to roughly group people as 'better', 'a bit better' etc, so don't get hung-up on that. I don't think you should have mentioned this to the class, given you were a guest teacher.
But you should have raised it as feedback to the promoter afterwards as it maybe an issue that he is unaware-of. As I said earlier safety can be an issue when people are at the wrong-level and the last thing a sensible promoter would want is one of his punters being injured (and suing). Let the promoter and regular teachers address this.

So although I don't agree 100% with your decisions, you clearly acted with integrity which from a personal prespective is the most important thing. Integrity is the one thing in life that cannot be taken-from you, it can only be abandoned by you.