Fix Your Transaction Policy

Seriously, this is the only online game I've played that, when your own software drops the ball and messes up a transaction, you'd happily take the currency while undoing only the purchase, instead of undoing the whole thing and return the currency. Even the notoriously greedy Korean and Japanese games don't dare do that; I'd say I don't know how anyone would pay real money under this policy, but since this game had been around for years I'm sure you have too many players willing to be robbed of real money every now and then to care about fixing it.