We have a 11 year old son who is being forced to attend meetings and have all the beliefs that ex has. I'm constantly being told what I should do and I'm supposed to go along with ex on whatever he says because apparently the "head of the family" continues after divorce in his world.
It sounds like your ex-husband is making unilateral decisions about your son's religious upbringing, does the child custody decree allow him to do so? If you are divorced, he has no right to "tell you what to do" (nor did he have that right while you were married; masters and slaves are not partners!).
I suggest discussing both these things with the attorney who handled your divorce. Forget the Elders, let him explain this to a real judge!