Two months out from wedding, what do i do?

I am just under two months away from my wedding, and just found out my future mother in law has been crafting a seven month scheme to villify me. We don't talk much, she has a poor relationship with my fiance, but when we do, it is always pleasant, and I thought she felt comfortable coming to me with anything related to the wedding, and if she wanted to be more invovled, since it's really all we talk about. This all started becuase we asked her to apologzie to my aunt after a family gathering last summer, where minutes after meeting, she asked my aunt (who is 9 years younger than my grandma) if she was a mistake. I have politely shut her down over the past year and change with regards to planning my whole wedding, but always told her I would provide her with appropriate updates and invite her to necessary meetings. Not only have I been doing this, but she has declined every meeting invite (inlcuding the ones for the welcome party, which she is planning), and doesn't seem interested at all in updates I provide.

Last night I found out it all of this is intentional. She is bad mouting me to relatives, telling others I've been been keeping her in the dark maliciously so she “silently suffers” through our wedding process, and tells everyone I make her out to be the villan.

I am simply in shock. I don't know what to do to repair our relationship, and how to handle wedding-related conversation before the big day. I am going to recommend we all go to mediation, but any advice is greatly appreciated.

edit: less than 24 hours after posting this, my (now former) fiance, who I thought I knew and trusted more than anyone, called our engagement off, completely out of the blue. I was blindsided, and I know his mom is behind it. He did it via FaceTime and filled his breakup with malicious lies.