Guild Wars 2

I’m trying to Buy Guildwars2 For my friends
Yesterday the buying system work normally.My Friend got the game.
And then today I wanna buy it for my another friend but the Page keep
saying that my Credit Card Information was incorrect.
and When I try to use my paypal it’s said ‘’An error occurred finalizing your purchase.’’
since My paypal and my Credit card work fine on paying WoW Subscription Fee
and other Products on the internet. I don’t know where the Problem is.

Also This Include Buying Gem from In game Transection appear in the same Error
Messages as well.

Btw.I’m living in Thailand.I don’t know if it’s region Restriction or not.

Please answer it.and Thank you for your Attention.