have you called the police? that's what they're for. to help you when you need them and someone is bullying you. i wouldn't let her steal my money. it comes too hard to throw it away. it sounds all nice to tell someone to get past it, but you've been cheated and you deserve the money back. call the police, the tv stations, the better business bureau, anyone who'll listen. send someone's man, larger than smaller, around to her house when you know she's there to tell her you want the money back now. he should have the merchandise with him, prepared for the return. of course, she'll insist there's nothing wrong, the money is gone, blah, blah, blah.... tape it on a hidden recorder and go straight to the police.
show them the stuff and the manual so they can see what's missing. ask them to take care of this. it's like a domestic disturbance. if she gets crazy, that's in your favor. i wouldn't wait another minute.