When trying to use my Tales of Monkey Island pre-order coupon code to purchase Bone: Out from Boneville, my coupon code did not seem to be working. It would not reduce the total for my order to zero. I decided to enter my code again on the final page, and try to process the order, but it would not let me proceed without entering credit card information. I entered my card information (though I'm not sure why for a supposedly "free" game), and processed my order, with the coupon code in its appropriate location. The invoice, however, seems to indicate that my credit card is going to be charged for the full amount.
I posted about this in a reply to another thread here, but did not receive a reply.
Why didn't my coupon code work? Am I doing something wrong? How do I get my money back if my credit card has indeed been charged?