Ex-best friend says I've been spreading rumors?

My ex-best friend talked about every one when we were friends (including our other best friend and I at the time) and also including the people she's hanging out with now. She said some REALLY messed up things. A lot of people witnessed this besides me. I told my new best friend in confidence how upset I was about her spreading rumors, and let's just say it got around. Now she thinks I called her a whore and I was sent down to the office for it; the guidance consular believes that I didn't and that she's just looking for drama. She keeps popping into my life with new drama and tries to be tough, yet she sends her friends over to be messengers. It's very immature. A lot of people think I called her a whore and she's getting defensive saying she didn't talk about anyone. This is really upsetting me because she's so fake. I want to mind my own business and for her to mind hers. What should I do?