Oh Belle, I am so sorry you had to deal with this. It is such a classic case and it sounds like this school just doesn't care or get it.
Everyone has good suggestions, and I suspect the folks who are used to dealing with FL know a lot more, but I agree about the documenting. Given what you were told, and you are willing, I would write a letter to the super. of the district, cc:ing the school, school board members, and any relevant state offices. It seems like it really can't go downhill from here, so why not push it as far as you can go (well, a lawyer would be the next step, but not sure you want to go there).
Best of luck, Cat
