When a credit card is used for online purchases, some security checks take place to protect both the seller and the card owner. Payment errors usually result in some sort of helpful message on the checkout page telling you what's wrong. But they can be confusing.
Obviously, the card number, expiry date and the CVV code on the back of the card must all correlate for any payment to succeed. However, a lot of people are not aware that a postal code and sometimes a street address check are made.
When the payment processor looks up the details associated with your credit card, it will compare address data it has on file with what you entered in the billing address (not shipping address!) on our North Arm checkout page. If the postal code of the two do not match, the payment will fail. The idea is that if someone tried to use your stolen or lost card for an online purchase, they are not likely to succeed because they'd have to know your address and postal code. Occasionally when people enter orders on our system they fill in the billing address field with where they want the package to go. Instead you should always fill in the billing address to match the credit card you are using and then fill in the shipping address with where the item should be sent.