Hire a mediator, get all of your finances in order (receipts of things you've spent on her bills, receipts on what you spent on your bills). You need to show proof that you don't owe her money for her rent. If your name is not on the lease, you don't owe her rent. If your name is on half the lease, and you paid your half, you don't owe her rent. She is trying to extort money from you. And the only way you can avoid that, is to get your finances put together, and then hire a mediator to help you communicate through via letters. Do not call or email her anymore. Have a mediator contact her. That is a good deterrent. She'll see that she can't successfully extort money from you, once you've got the law on your side. Try to avoid the 'tit for tat' back and forth with her anymore. It will only escalate (which is her goal, so that she can make it look like she is the victim, which of course is not true at all).