Can you send an email to the moderator if someone else is signed in as you on yahoo messenger?

I signed in to Yahoo messenger today and in a few seconds, a window popped up saying that i can't get on the messenger because it said that i am logged in on it on another computer or device. No one else but me knows my pword. But there is this one girl that cussed me and my best friend out and she googled us and she found out my pword for both of my email addresses. She also manned us. Her name is Brittney Leigh. (bratty_brittany i think). Please answer my question.