You can maybe send the developers themselves a message: firstname.lastname@example.org
Serious question: why would they (the “developers”) bother about my emails? They are clearly doing this in bad faith, ripping off free software like that to sell some ads, why would they care at all about complying with the GPL?
You can threaten legal action and maybe they’ll stop. Doesn’t hurt to try, though.
Just sent an email their way.
This is why GPL exists. If the app was MIT, you’d be screwed (and users too)!
Imagine being that developer, whose job is to put ads on open source apps #fuckmylife