What can I do about racist, harassing texts, authorized recorded phone calls and voicemails defaming our character by my fiancees ex girlfriend?

She has been stalking us, she has contacted his job trying to get him fired over something he never did. She has filed false reports of domestic violence while he was with me and then dropped them because they were all falsified reports. She drove to my complex to send photos of the sign threatening to send cops and all of sudden there are cops knocking on everyone's door for my ex because she doesn't know my address, my real name, nothing. There is no reason for all of the stress she is causing and I don't know what to do. She leaves messages calling me an "N", a loser, a "pothead", telling her kids while on the phone that they are not a family who likes "N*****s" and also claiming we have stds. This woman is clearly unstable and I need to act now before I really start fearing for our lives.