Jerk at my school knows my mom and is making my life not worth living?

she is a huge jerk and i hate her! her name is nika she treats me like crap and says i am ugly and not dating material she prank calls me tps my house ands spreads rumors about me she is a hoochie girl and calls herself pretty when really she should be on a street corner she knows my mom from way back and decides to come over and steal from me i called her names and did all the stuff she is doing to me but she made my life even more misreble i tell my mom counsoulor and dad but none beleive me because nika is a little princess i don;t know what to do anymore but i have had enough!