Please feel free to contact us via the Green Support Messenger but, for customer security reasons, our payment system doesn't give us much information for failed payments. Often it will just say: "The transaction was declined by the issuing bank. The merchant should attempt another card".
Firstly, you might need to speak to your bank and confirm that the payment is ok, as sometimes their fraud protection mechanisms can be a little overzealous. Otherwise, it's usually best to left the system try a couple of times and, if it doesn't work, try another card.
If you need to update your payment details, see “Changing your card details in the Payments section.
We only accept Visa & Mastercard, not the likes of American Express.