I agree with qtns2die4, if you've got the phone to stay in contact with her then DO NOT SEND IT - her mum will go balistic and could go to the police. If its her phone that got left with you, then return it, but if at all possible send it via a family member.
Her mother has gone into shock and just shut down any thought of the situation. She cannot accept that her daughter is capable of rational thought. If your girl can stay strong for you, she's in for a very unhappy time, but she might get her mother to very slowly come around.
You are very much stronger than me. If I was propositioned and I loved her, I don't think I would be able to resist, in spite of all the risks.