I've had an encounter with PaymentWall during a purchase in an online game (Black Desert Online). They blocked payments from my account and were not willing to provide a reason why they've done so. Prior to PaymentWall providing their "services" for this online game, I was able to make various purchases without any trouble.
Upon processing my ticket, they actually demanded to receive a copy of my passport and credit card, which is in my opinion quite insane. Not even large and widely recognized platforms such as Steam or Battlenet have such ridiculous demands and I've been using those for quite a while.
My Advice to companies planning to do business with PaymentWall; avoid these people. This is either a scam, passing info and documents on to third parties, or a bunch of amateurs not understanding how to properly conduct business.