My River Island
We’re not able to specify why card payments are declined as the payment process involves both our systems and your bank’s.
In the first instance you should double check you've entered all the details correctly, that you are using a card which has not expired, and that your billing address has been entered at checkout exactly as it appears on your bank statement. If your billing address is incorrect it will cause your payment to fail - this is a security measure banks put in place to protect your security.
If all else fails then please try an alternative card for payment - we accept all major credit and debit cards, as well as PayPal.