Hi MKB,
Welcome. You and your feelings do matter. I'm glad that you're here and reaching out to others who understand what you're going through--it really helps.
I sent her into a total melt down one day because I was so sick of the attacks about things that I had not done and I countered her lies with the truth. How do you change if the things you are accused of doing are total fabrications?
Here's one of the hardest things that I've learned from my experiences with a BPD mother: there's not much you can do about the attacks. Sometimes people with BPD (pwBPD) will "paint you black," so to speak, and tell others unflattering or untrue things about you. It hurts. That said, I've also learned that people who know me well will also see through the stories and/or not let them affect the relationships between us. It takes a lot of patience and good self-care, but over time, I've learned that it's best to not engage or get defensive. A simple, "Oh, that's what you've heard? Well, that's between me and X," is I respond now.
How are you taking care of yourself? What kind of support do you have?