So, some features that will break gold sellers spam:
- Doesn’t allow the player to send 3 equal messages in a short period
- Doesn’t allow the player to send 3 equal global messages in a short period
- If the player insist, get muted for some minutes
- Add a spam report option, currently we just have bot report
and with it the player that is spamming could get a minute of 10minutes or more you know? and for every time it repeats increase the time
I know gold sellers could be botters as well, but separate things helps to make the decision of what to do, the game system could analise the last chat messages of the spammer and decide if he will get a mute or not 
So, it is really easy to do, annnd the spammers are THE ENTIRE DAY on the cities spamming, why IMC guys doesn’t see it? impossible 
My friends used to joke that they are IMC games guys selling gold to get more money hahaha

