You haven't actually exhausted the food chain...if you really wanted to, you could actually sue the teacher for not implementing his documented accommodations. She is personally liable.
A little less extreme, but you could also file a complaint with the state DOE. As you've already spoken to channels, it makes sense to give them a heads-up that you are concerned enough to make a formal complaint, to the DOE/BSE, and to OCR.
Without leaving the district level, you may also request an immediate reconvene of the IEP team. I don't know how far up "all the way up the food chain" is, but if you do go the reconvene route, make sure to invite a district level special ed administrator.
