When it comes to the checkout, you must enter the correct address, CVV and expiry in order for the sale to be processed. If you enter a piece of information that does not align with what your bank has on file, the checkout will decline the sale. 

Your bank account also has a set of risk rules to prevent fraud. If you fail the checkout multiple times within 24 hours, then you may be blocked from the checkout for 24 hours. If this does happen, you can simply wait 24 hours from the last transaction attempt and try again with the correct information, or call your bank to unlock your card.