The exchange system between players is fine, but it is very abused by gold sellers, that players add price to the auction house, causing many to lose money selling without knowing it or due to ignorance.
I think the best solution to eradicate the bots is to eliminate the exchange of gold and its delivery by mail, and add fixed prices to the auction something like black desert online does, in this way the only viable way to use the bot would be to use it in the same account and it would be easier to penalize in my opinion.