If your payment fails then your order will have also failed and you'll need to complete the checkout process again to place your order.
Check to ensure your card details are correct before submitting or if you have another card you could try that. Note that we are unable to accept American Express cards at this time.
Alternatively we also offer payment for orders under the value of £125 via PayPal. If you have a PayPal account you can log in to complete payment or if not you can pay using a debit/credit card by selecting that option at the PayPal payment page.
If you still need help then please raise a support ticket.