What can i do in this situation ?

I'm writing this anonymous because i'm embarrassed.

My mother had an affair a few years back.

We all found out & she & the guy ( C ) decided to break it off. My dad forgave her & they're doing good atm.

( C) 's wife has been texting & calling my dad saying my mother has been texting her talking shit. Calling her names. My mother says that is not true. She says she has stayed away from C & his wife ever since we found out. My dad & mother had been doing good up until C's wife called him & sent him screen shots of messages my mom supposibly sent her. My dad sent me those messages & i just cannot believe that is my mom. It sounds nothing like her, the typing, the commas , the periods.. NOTHING Like my Mom.

Do y'all think we could get a restraining order or sue them for defamation?? What wouod y'all do in our situation?

* Please no judging. My dad forgave my mother. I know she fucked up, but everybody makes mistakes .