This girl is Haring Me On Aim?

this girl is like haring me on aim, and i block her but then she gave my aim out to all her friends, and made a new aim. she goes to my school. every time she IMs me, she sounds really nice, but then in school she laughs at me and makes fun of me. then her friends join in, then the rest of her cl. what should i do? and no the teachers won't do anything about this. and neither will my parents. they just say to ignore it.