Users will input their credit card details and submit however they often forget to also select Card Payment as the payment method.
Therefore it returns an error. Many customers realise and then select the option, some report it (quite upset sometimes) that it's not accepting their card and who knows how many actually just give up their order altogether.
Could it be coded that as soon as the customer enters one of the credit card fields the payment method is automatically selected?
Just enter card details without selecting the payment method and then checkout.