TLDR: Not actually MindArk's fault
I've had a very long back-and-forth with support about the issue since May 23. It would be a wall of text to go through it here but the short of it is that it is a payment processor issue and MindArk is aware. To quote one line of a response I got recently:
"When they have confirmed the issue is solved, we will announce it on our website."
I can't speak for MA but from all the info I got from my bank and the responses I got from support.. I get the impression that the issue is that their payment processor has switched to a more secure authentication protocol that is not 100% compatible with many other financial institutions (especially those within the U.S.). 2FA and how it is handled between the two regions is extremely different and the vast majority of banks in the U.S. in regards to debit cards, or even credit cards, do not follow the same 2FA procedures. Many (most) of the biggest banks in the U.S. do not require 2FA to log in to your web panel or even have an opt-in 2FA option for your online banking OR your web-based purchases... they instead use various security algorithms to combat fraud.
Considering that NETS doesn't even default to English when calling their customer support line (I know from a few attempts trying to contact them myself - STAYED ON HOLD 30+MIN EVERY TIME, NEVER GOT THROUGH
) it really just confirms my suspicions that they are very biased towards EU authentication protocols.
Unless the payment processor (NETS) decides to go with something more lenient I'd probably look into different card options that are more in line with their security protocols. Considering they went this route AND they couldn't hold onto PayPal as a processor I'm going to just make an assumption that there is A LOT of fraudulent transactions/attempts coming from the U.S/stolen U.S. Card Information ?
Personally I opened a new account and transferred funds to it, but I'm hoping that they just implement/code a checkbox on wire transfers that says "RECEIVE MY DEPOSIT AS STRONGBOXES+KEYS INSTEAD OF PED." Finding a debit card provider in the U.S. that has options for 0% Foreign Transaction Fees AND 2FA seems very difficult
edit: Not saying that getting a card at a new bank is the only option.. just an alternative until NETS (hopefully) fixes the issue. I can't imagine MA isn't contacting NETS on a daily basis due to the amount of money they are losing