Amazon.com - Amazon Fixed the Problem
I received a holiday gift certificate for Amazon from my boss in December 2011. I live in Europe and usually order from their European branch in the U. K., but the gift certificate was valid only on the U.S. website. I placed my order using the gift certificate and waited.
And waited. I never received the package. I sent Amazon an email (to which a customer service representative almost immediately replied) and was told that the shipment was lost. (I personally suspect the Czech Customs Office, which holds any package from a non-EU country with a value of more than $30.) Anyway, I ordered the same two books again. I received an email confirming the order, and I saw that I was being charged for the full amount and that the gift certificate was not being applied to the price. I wrote another email demanding that they cancel the order immediately.
Not only did they cancel the order before it was charged to my credit card, they reactivated my gift certificate, refunded the amount for the original order (the amount not covered by the gift certificate), and gave me a "goodwill refund" for my trouble. The refund wasn't much, but it did serve its purpose: I will continue to shop at Amazon.