My guess with all of this is that these are Kronos that are purchased with the intention to charge back the payment after they have sold the krono in game. If that's the case, I can see where DBG is between a rock and a hard place.
I mean, how do you deal with that really? What is the limitation of time for which a charge back can be applied by a bank? Is it days, weeks, months? If DBG was to make you wait to get your Krono you purchased until it passes the time limit for doing a charge back, that would be insane for the player. It would be like putting a Krono on layaway for later in the year.
If they go with a trusted purchaser system (which I think they do), all the bad people have to do is keep creating "good" purchaser accounts by making a purchase they don't charge back, and a month or so later when it is flagged as a "trusted purchaser", make purchases and charge them back. There's literally no way for DBG to keep this from happening.
It's pretty fucked up to put it bluntly, but this is the world we live in where any jack ass anywhere in the world with an internet connection can fuck any company they want 24 hours a day, and there is no shortage of fucktards in the world willing to screw you to better themselves.
Honestly, there is only one way I can think of to make Krono purchases secure, and that would be to go to selling a Krono card at retail stores (and online via Amazon) like they used to do with Daybreak Cash. That way, the purchase of the Krono card at the store is a transaction that is separated from DBG in a way. Let Walmart and Amazon deal with the bad actors so to speak.
If they wanted to make it even more secure of a purchase, don't offer the Krono cards via online sources like Amazon. Make it a Walmart, Kroger, Target, etc elcusive purchase. In other words, eliminate the 3rd world countries from the picture altogether.