I haven't talk to my female friend in months I'm also female Why is she still trying to contact me?

She keeps calling my mom asking for my number or tell her l need to call her. Recently she contact on of my nephews and said the same thing. I stop talking to her because it was a toxic friendship. She has low self-esteem for years she has been trying to drag me down. She Would criticize my appearance like say things like my nose is wide . Indirectly she said one time one of her friends can wear there hair of of there face because she has nice features and in the same sentence she says why don;'t you wear your hair in your face. Yea, I love myself but the breaking point was when she was telling other people how great her life was and I don;t do anything like I need her! When I had a male friend she was jealous. I couldn't take anymore abuse telling me she was going to ride with me somewhere and have me waiting for two hours and say I'm not going. I live three hours from her! She lives near my family back home I moved away. Anyway hI feel like she is threatening me telling people I need to call her. Should I get a notarized letter telling her to stop haring and if I hear talking about me I will sue her for slander