[peterdoo]

When such things happen with my issuer (online or in a real shop), I contact them by phone. Either they tell me there was a mistake in my data used by the shop for authentication (address, house number etc.; some shops take this data from delivery address or their customer databases). Or they just tell me I should try to pay again and then the payment is approved. I suppose they have a possibility to mark a rejected transaction in their system in a way that it is accepted if repeated.