I have never had this much of an issue with any payment system. Paywall blocked my card, I sent in verification info, they said they unblocked it, then it was blocked again, then they once again said it was unblocked, and AGAIN IT GOT BLOCKED.
Paywall has strict policies as any other payment company that deals with US federal laws but their programming in the system sucks and I feel like there may be others on this server who decide not to donate simply because it's paywall or they just got blocked as well.
Paymentwall sucks with credit cards, use some prepaid cards like subway, mint or any other that is available. Works like a charm, you won't even have to give them your card details, and you can buy those for cash if you're in a normal country.