Hw to deal wid ppl hu hv faltu attitude?

i hv an enimy of mine who is like always showing off!! she lies a lot about me!! ALOT!! wen i dnt tok to her she is like always bitchin about me nd today she crossed it!! she ws like soo ughrr!! tht she asked several ppl tht will u be my partner in ananya's bitchin!! i mean wtf? plz plz plz help me! i need it badly she is a mad person! she is takin away all my frndz wd her politics i sumtyms feel like slappin her nd even hitin her hard!! guyz plz help!! i wanna kill her