Hi, there and

I'm so sorry about all the troubles you've been experiencing with your Mom; so many posters on this site will be able to commiserate with you! I'm sorry about your twin sister; that must feel terrible, and to have your Mom make you feel bad about it all over again must be so sad... . You have my condolences.
I can understand your wanting to have no contact with your Mom, but there are other ways to cope with her behavior... . You are not alone, and we have many resources here to help you. Here are a few of links to get you started:
How a Mother with Borderline Personality Disorder Affects Her ChildrenHow to Forgive an Abusive ParentBOUNDARIES: Upholding our values and independenceTOOLS: S.E.T. - Support, Empathy and TruthI am here because of my adult (36) son, and not my Mom, but my Mother-In-Law is undiagnosed BPD, with the same behaviors and symptoms of your own Mom (I've known her for 42 years!). I found that once I learned the communication tools in the link above, in order to be able to communicate better with my son, my relationship became better with him immediately. And, the remarkable thing is, once I learned how a BPD brain works, and was better able to manage things with my son, I applied that understanding and the tools with my M-I-L, and things improved with her, too!
Please tell us more of your story, and ask more of your questions~~It will really help, and we are here for you whenever you need us