GMs have stated multiple times that they cannot accept screenshots and/or videos as evidence of any sort of “illegal” activities because of the fact that they can be altered. They can only accept in-game logs showing chat and any other activity since those cannot be altered.
If there is no real-money being traded, selling content for in-game gil is not against the ToS. The only thing that would be against it in that situation would be if the people selling the content actually logged into the buyer’s account to do the content. If there’s real-money being involved, that’s a different story, but for in-game gil, it’s technically not against any rules.
All this being said, the GMs can ban one group, and another will just pop up. This has been happening for forever, so it’s doubtful it will go away any time soon. I just ignore the adverts whenever I’m browsing PF.