Friend lost a laptop - accusing and demanding money

Friends lost a laptop at her room. My boyfriend and I, her boyfriend and she, her roommate and her boyfriend were there. She accused one of us of stealing it and said she would call the police. I panicked and left the place, as my mother would know about my boyfriend in that case. She demanded money for buying a new one. We paid 10000 by getting it from my boyfriend's father, and she asked 10000 more. We said we were just students, we can't give any more. She and her boyfriend have been accusing me of stealing it and is telling people about it. I haven't stolen it. I would like to file a defamation case, but I can't move anywhere freely, my mother has a weak heart condition and would not bear the news. They have no proof that it's us. They are just running their mouth. I feel very hurt and have been feeling suicidal and anxious. I'm afraid that I won't be able to complete college with a clean record if this continues. I have exams as well. I can't concentrate at all. Please help. I really hate being accused like this. I am ashamed to have called her my best friend once.