Sorry to hear about her experience. Your question is regarding the Islamic laws and for that I called the office if Sayyid Sistani and the following is what they had to say: The consent of a girl for a marriage is extremely crucial.
Therefore, if she is unhappy with it. The entire Nikah is void. On the other hand, she must also know why she is refusing this proposal. We have to have a solid reason to call one away as a suitor. Further more, I would ask this sister to:
1- get some counselling and also find an intermediary who will be able to speak to her parents and inform them of her thoughts and feelings. Furthermore they also need to be told about her Islamic right. (Pls refer to the second paragraph)
2- she must make dua. Ask her to pray plenty for herself to Allah (azj) for a great suitor and inshaAllah she will be soon settled.