Why not just ignore it, send them a message back telling them why.
It's not like they can actually go to court, because then they risk getting charged with perjury and then going to jail. That's not worth the fraction of a cent.
I'd write to OnlyFans too, in some super public way that lets a whole bunch of other people see it, so they can't just brush it under the rug and actually have to deal with it. Do they have a Bluesky account?
@rastilin @gjhbkk3
The problem is that Google treats it seriously, and it's not good for my business if Google decides my content is all stolen from elsewhere.
So I end up having to respond to every and any DCMA and waste my time, even though it's someone else stealing photos.