I am so sorry that you’re going through this, I hope you’re still around the forums!
My husband and I went through something similar when our daughter first entered Catholic school. We sought counseling within the Church as well and were told to just ignore the issues, but it sounds like you have it much worse. I would, honestly, set up a time when you can speak privately with her and lay out the issues. If your child has a learning disability, explain this to her. Tell her that she may dislike you as much as she wants, but that you walk with Jesus and Mary, and assuming she too is Catholic than you have a commonality! Tell her she is negatively affecting your children and her own, and that this sort of thing needs to be kept out of and away from the school.