Never seen such a poor support like in this game!

[KageTokage]

If that's the case, banning them forces them to register new accounts, no?

If they get banned, they'll register and start leveling new accounts within a few hours. The problem is that takes them less then 24 hours to go through the entire 1-50 leveling process, so they get back to farming gil in scarcely any time at all.

They're so efficient that trying to combat them with bans alone will not work unless they do it on a daily basis.