How far are you from where she lives?
Foremost, I want you to realize that you are far well-grounded that she is. Don't ever stoop down to her level.
You know you are not doing what she says you do, so, what's the use of worrying over it? Say, pffft....not true (just to your self and/or your husband, then dismiss and IGNORE all her "attention getting' tactics.
She is a very insecure and a needy person. Wants all the attention she could get no matter what - you are giving her what she wants by merely worrying about her.
Don't even give a dam...she'll eventually realize (who knows when), that any of her antics is not working, so she'll tire over it. Hoping she'll leave you alone.
Do as you normally conduct your business at home and with your friends and in-laws. During family gatherings, just be civil....garbage - in, garbage - out.
Stick here with us in the forum. Share and pour out your negative emotions here, but don't show her your vulnerability. The more you show it to her, the more you enable her to do as she pleases.
Been there, sweet. I know how it feels.