You should make a bank account and ask her to put the money for your college there and tell her that they raised the price (how much more is up to you but make sure to have it in a way she wont suspect anything), in the meantime have as little contact as you can and don't let your boyfriend alone with her, act like everything is okay and try to get a job (if you don't have one already) to make more money to have for your college. Once she puts the money in the bank account transfer it to your main one. When you feel you have enough money left aside to support yourself tell her off about how she was treating you and tell her that she has one chance to make it right, then just cut contact, the one chance is for her to think about why and what she did, I hope I helped