You don't understand a thing about the law. There are laws actively preventing interfering with individuals in banking. Again. This is a suit waiting to happen, or more, a political smackdown. The Japanese are already starting to take notice of the attack and retaliate.
If they shut down *all* payments because they opened a suit, that would be ruinous for *mastercard* in court, not for itch. It's just a matter of whether itch can afford the suit itself.