I hate my sister
Do you mind telling me why you hate your sister?
You should understand that I don't want to communicate with her and that's that.
If not talking to your sister gives you peace of mind then you can stop talking to her. No matter what happens you cannot change the fact that she is still your family.
She's a bitch and I hate her.
You're entitled to your feelings, and if that includes not talking to your sister, so be it.