If you want Snail to do a check on a user, you need to send an email to SupportUSA@Snailgame.net
(with proofs such as pictures supporting you accusation of course). I once reported a user for having both Purple Death and Hidden Prowess. That account disappeared the next day or two, could be erased by Snail or the owner of that account, but it was taken care of.
Again, I doubt that Snail hasn't done that already. Expressing your frustration here do you no good. If you expect to see that account being banned, prepare to be disappointed.
Oh, about your argument of buying gold on "black market", there's another thread about that already, just look for it. If those are not hacked gold, and as long as Snail get their full share of the deal, that's not cheating. Let me ask you this, if you are at Best Buy and they have a deal 30% off a Sony TV, are you gonna buy it or are you gonna say "oh that's cheating, I must come to Sony and buy it full price from them", then you try to contact Sony telling them Best Buy is selling their product for 30% off and want Sony to do something about it???.