Family issues!! Need advice

I haven't spoken to my Mother and older sister in 3yrs reason is my Mother is very manipulative and deceiving an she likes to pin her kid's against one another I've known since I was younger that my mom was very abusive and controlling I would watch verbally and physically abuse my older sister and I vowed when I got older I would save her from her well as the years went by my mom had more kids to sound of 10 I'm number 2 and I've also been very badly abuse physically,verbally,and sexually to wich I've never told a Soul to protect my Mother but my my mom on many occasions has I deserved everything her husband did to me No kidding I'm not making this up ...long story short she has successfully completed the task of dividing my older sister and I for 3 years now she stay with my older sister and her husband and is continuing her saga of mental horror on her and her husband

I've turned completely cold to my sister because we've been through so much together why would she let that beast of mother come between us ?

Sorry I'm so long winded please any advice would help 😬😯😢