Usually, if you are seeing a prompt that your card payment has been declined, this is being done by your card provider as opposed to Design Cuts.
If you know you have sufficient funds on your card, we would recommend ringing your card provider to check why they have declined the transaction. Your bank may be declining the purchase as we are based in the UK and this can be deemed as a foreign transaction. Once you notify them that you are aware of the charge, you should be able to proceed as normal!
If you are having problems though, please do get in touch!