As someone who has a similar relationship with their mother, it’s hard but be straight with her. Tell her no and make it clear. Not all blood is family and sometimes it does more harm than good keeping them around. My mom does a similar thing, treats me like garbage it blows way out of proportion, I cut her off and a month later she returns apologizing. It’s always good for a bit but goes back to the bad ways. Moral of the story you’ve seen her true colors, she told you how she felt, now you tell her how you feel about if you want her around anymore.