Can I get a protection against my husand's daughter's mom who has a mental problem?

My husband found out he had a daughter in foster care. After ensuring she was his, the mother agreed to sign over her rights. I then adopted her and have raised her almost her entire life. She has never known the bio mom. The bio mom had a lot of mental issues and other children in foster care as well. Since I have adopted my daughter, she has called my husbands work claiming he ran away with her child and is married to him, has emailed us on and off for the past 4 years, despite our trying to block her as she is very well aware we do not want to be contacted by her at all, and it just goes on from here. Do I have any legal rights or actions I can take to get a restraining order or anything to get this woman to leave us alone? She is mentally not the most stable and I get scared that she will hunt us down at some point if I can't legally get something in place.