How should I advise a friend falsely accused of stealing told if she retaliates it will make things

OK so, my friend worked for CVS Pharmacy as a cashier. She always put her crappy job before most anything else, made herself available at their beck and call and always put the companies needs ahead of her own. She's just that kind of person; committed, over-trusting, and honest to lettert but has almost no business sense. So she was completely taken by surprise when someone from loss prevention called her into the office regarding a customer complaint about not honoring a coupon that was outdated by 6 months and that she was suspended until they made a decision and would let her know on Monday. That was 5 Mondays ago now. After the first 2 weeks I suggested that she file for unemployment to get the ball rolling and to find another job only to find that she was ineligible for services because she was fired for stealing. So she's been applying to every job she can find including a retail job she had previously held that she had left for a better job. She found out shortly after that the application was rejected by the server. And then yesterday we receive a civil demand letter telling her that she must pay $500 for some mysterious merchandise she supposedly stole and that if she retaliates that the charge will go on her permanent record. All this and yet she has yet to have been presented with any evidence of this alleged theft or even been told (as side from the letter) that she was terminated for theft. I'm really not sure how yo advise her but I'm personally not one to just give someone money because they say I have to for no apparent reason. In my opinion this constitutes defamation of character at the very least if not some level of extortion on the part of CVS. I'm just looking for some advice on how to guide her as I'm not an attorney and don't want to point her in the wrong direction and make matters worse. Thanks in advance.