ST, I would absolutely slap her with a defamation suit. Make her expend resources to "defend" herself. Some people should pay for their actions. No accountability on her end if she can spew nonsense that negatively effects other people with no ramifications whatsoever.
M: 34 W:34 D:7 D:6 S:3
M: 9.5 years T: 12
OM found & BD (by me): 9/19/18 IHS begins W informs me she's moving out: 11/28/18 W files: 12/21/18 D Final: 2/25/19