Dear Robyn,
It is everybody's right to expect to be treated with dignity and respect. This applies for everybody in your life, including family. I would tell her that unless she chooses to do this, you will have NO contact with her. You will only be willing to speak with hear once she learns this. Just because she is family, it doesn't earn her the right to be emotionally abusive to you.
In the meantime, join as many social groups as you can, and make some friends that are worth having, who DO treat you with dignity and respect. They are out there, and you can find them. Make them your chosen family, instead of the ones who treat you badly.
This is what I would do, in fact, I have already done it with a few family members.
You deserve pace of mind, and to be valued.

Lily