There are two ways of paying for Premium in this game.
The first option is to buy Premium by bankcard. Normally the IBAN should work ... (wich country are you paying from?) A second option is to pay by PayPal. PayPal is used all over the world and if you have a PayPal account you can upload credits to your account on all different ways, including creditcard.
I hope to see you soon in the game with your own created shirt and lost of more extra's