so there's this website called ebooks tree -- i'm not giving them traffic, just google it and it's the first result. if you search your ao3 (or wattpad, if you publish there?) username you might find that one or more of your stories have been made available as pdf "ebooks"
AO3 and the OTW are aware of the issue: AO3 has already taken steps to make scraping more difficult, and the OTW is considering further steps they can take as an organisation. The OTW also advises sending these people DMCA takedown notices
however please read this before you send them anything, ok? ok <3
(i'm not around to talk about this as i have a fic chapter to finish today but i'll be around tomorrow if you have input/want to vent/etc)