I can’t do this anymore

Four years ago, my sister and her kids moved in with me and my mom. Prior to that , me and my mom lived a pretty care free life . Although I was being bullied for my weight and made fun of by those in my church , I never let it get the best of me and continued to go on with my life (I was 11 at the time). Two weeks into her moving in , she began to show her true colors and fight after a fight unraveled in my home. She said many belittling things such as telling my mother to her face that if she were to ever die she would never attend her funeral , and to tell no one to inform her cause she wouldn’t care.she knew no one except my mothers friends so she called all of them at the time and fought for them to be on her side even though she was completely wrong. My mom kicked her out and got fed up . Fast forward 1 month. She calls my mom apologizing and being the kind women that my mother is , she let her back into the house. Nothing has changed for the past 3 years after that. She continues to degrade and belittle everyone in this homes and walks around on a high horse as if everyone should just do what she says and here’s the kick : she pays NO bills. No Bills. Yet for the past 4 years she has put into her mind that she has completely control over everyone and everything . Just about a month ago she finally got a sustainable job and is finally contributing to the home. But all she can do is complain about how all her money is being spent on bills and such . She only has to pay 600 a month and makes 1700 a month may I add. She constantly throws disses at me but being the person that I am , I simply ignore her and don’t give her the time of day. After years of emotional and mental abuse I am officially done. I can’t do it anymore. The disrespect to my mother is getting to me and I can’t take it anymore. My mother works 15-16 hours a day and when she comes home , she has to constantly take criticism from this bitch. Just yesterday she called my mother retarded and special. My mother doesn’t speak English clearly so she couldn’t quite understand what special meant, so my sister constantly threw that word around . There’s so much more I can write but I just don’t have the time. I really need someone’s help. Please. I’m hanging over the edge.