Problem with credit card
Best thing to do is file a support ticket at https://en.support.guildwars2.com/ (ask a question)
Arise, opressed of Tyria!
ArenaNet Communications Manager
I have problem with buying gem in game and buying Guild wars 2 by my credit card. When i tried to buy gem in the game, it repeating said that credit card approval failed. Also, i want to buy a new guild wars 2; however, when i try to complete my purchasing, it shows me “The credit card information you entered was invalid. Please try again.”. Therefore, i went to my bank to ask them about my card and does they block anything. They said no and my card is fine.
We’d love you to be able to complete those transactions, so please contact Support by filing a ticket through the “Ask a Question” tab on that linked page. They will be able to assist you. For tips on what information to provide in a ticket — mostly intended for security reasons to establish that you own the account — please read this post and provide as many suggested details as possible to expedite the ticket.
Oh and there’s a nice FAQ about the BLTC/Gem Store that you might enjoy reading: https://forum-en.gw2archive.eu/forum/support/account/FAQ-Gem-Store-BLTC-Trading-Post/page/42#post2064549
Thanks for your support of our game.
Communications Manager
Guild & Fansite Relations; In-Game Events
ArenaNet