Who in God's name designed your payment system SE?

[Tupsi]

Well, aren't you fortuante. No, no unsupported country, nothing like that at all. And by the way, SE's payment processing is not a Japanese bank. Even if it was, 99% of card payments are handled by a very few global payment processing organizations, it's all quite international and quite well regulated. If you use a Visa card, it's a visa payment, it has little or nothing to do with your bank.

Yep, I use a visa and BoA which is notorious for having random issues with some payments due to "security" reasons which will prevent it from going through - so it definitely does depend on your bank when it comes to online payments.