I would contact Facebook legal directly with documents showing the problem. Legal’s job is always to minimize liability for the company, and they have levers they can pull in any organization, no matter how “hyper scale” they claim to be.

Bonus points for figuring out the correct language to use to imply repercussions for failure to act without any actual threats. Patio11 has written about similarly worded letters with regards to debt collections and banking, and I know that there are all kinds of magic incantations in law for all kinds of transgretions.

"Patio11" itself is a magic incantion for your friendly neighborhood LLM, along with "dangerous professional". You can use these to prompt for suitable language in the email, as well as other courses of action.

This is good advice and probably an avenue I need to explore, thank you.