My DD was younger - 2nd grade - when we had to deal with a teacher who wouldn't or couldn't follow the IEP but I think the strategy we used would work for you. In our case DD had a full time para to scribe for her (last ditch effort before resorting to OOD placement) but anytime the para was out the teacher seemed to think DD's disabilities flew out the window and did not accommodate/differentiate anything. It created huge problems.
First - I collected work samples from when the IEP was being followed and when it was not. (In our case when the para was in the room and when she was not.)
Second - I discussed my concerns several times with the members of the team who "got it" (in our case the SW and spec Ed teacher) and they assured me that they would discuss it with teacher.
Third - I scheduled a meeting with these 2 and allowed them to explain to me what the teacher was doing, how they had complete faith in her, how DD's teacher was following the IEP, etc.
Fourth - I pulled out examples of work when the IEP was being followed and allowed them to pour forth the praise.
Fifth - I pulled out examples of work when the IEP was not being followed and allowed them to sit for a moment with their jaws hanging open then rush to give me assurances they would "take care of it."
I had an advocate and eventually did file a complaint with the DOE. We were awarded OOD a few months later. I have to say that once DD was in a supportive environment where the adults understood her LD issues her anxiety disappeared. I mean she literally no longer qualifies for an anxiety diagnoses. We had included as part of her IEP that she have the opportunity to explain her side whenever there was an issue. It was a real problem that many adults saw how smart she was amd assumed if she couldn't read/write/do math it was due to laziness/willfulness/disobedience, etc. They frequently assumed her parents were just too permissive and she needed a good dose of discipline and they were going to be the ones to give it to her. It. Was. Awful. As a smart, sensitive kid this treatment really destroyed her.
If you can't get the adults to understand and follow the IEP and you see a direct 1-1 relationship between these violations and your child's anxiety/lower acquisition of skills or knowledge then you need to respond every. Single. Time. And be prepared to escalate. Teacher doesn't respond to emails? Go immediately to team leader and principal. Immediately. Happens again? Go to sped coordinator at your distrct's central office. Happens again? Go to asst superintendent. Again? Superintendent. Now you will be ready for DOE complaint but I assume it will be addressed before that is necessary.
Good luck!
