What Do I Do If My Payment Was Declined?

If your credit card was declined and you believe it shouldn't have been (you are not over your spending limit, the information entered is correct, etc.) the best course of action is to contact your card issuing bank. Their phone number should be on the back of your card. 

You will want to inform them that the card is being declined for a transaction you would like to approve. The card representative should have a list of declined transactions listed by charge amount and merchant name.  The merchant name will be "CartStack LLC".  

The representative should be able to "whitelist" charges from CartStack, at which point you can attempt the purchase/upgrade again.