Maybe its time to stop dealing with only the teacher.

Whenever I needed to discuss issues related to acceleration, being challenged, etc I would always arrange a meeting with the principal, assistant principal and any appropriate teachers. I found there was less room for miscommunication and emotion. I was always blunt and straight to the point (not necessarily a positive personality trait LOL)but then again no-one was left guessing, and in my case it worked!

I hope this helps.
Matmum