In general, if you are seeing the error "Your credit card could not be charged" on the front page, it means:
Your card provider declined the charge. This could be because of an overdue balance, because the card was flagged for possible security problems, or other issues that your card provider can tell you about.
The address and zip code on your Listbox account do not match the one for your credit card billing address. For the security of transactions, most credit card providers require that we provide your address as an additional verification method. If you have recently changed the address and zip code on either your Listbox or your credit card account, those two pieces of information may no longer match. Please update your Listbox account information to match that of your credit card.