I am about to go live with my first store for a client. However, we noticed a problem with our payment gateway - Realex - if a customer enters a wrong/rejected credit card number. In that case, an error response code is returned. If the customer now simply corrects the credit card number with the right details and tries to pay again they receive an error code that the transaction has already been processed.
Realex tell me this is because each transaction at their end needs a unique order number. So even if the payment is rejected, that's a transaction on their system and if the order comes in again with the same number it rejects it as a duplicate.
Right now, the customer needs to start from scratch with a clean shopping basket in order to get a new order number. That is not really a long-term option. Is there any better way around this?
Realex say that the format of the order number is irrelevant and could be a completely new number or the previous number with another character attached.
I'm lost. All help appreciated.