FAQ:
What should I do if I am having trouble ordering a card?
If you are having trouble placing your order, the payment method associated with your Apple ID may not be supported. Cards currently supports payment via Visa, Mastercard, American Express, Discover, and JCB only. You can change your payment method on your iOS device by tapping Settings > Store > Apple ID, or in your Apple ID account settings in iTunes > iTunes Store on your computer.