I kept getting authorization errors, and couldn't figure out why, so I called their billing department.
As it turns out, their billing system attempts to authorize the entire amount off the credit card, ignoring the gift card balance on the site. It only actually bills you for the three-dollar balance, but if the forty-eight dollars isn't there, it can't authorize the credit card.
That is the dumbest thing ever, it really is. Even the call centre girl thought so.
Three dollars of tax. And I can't have my books.
FUCKING Chapters. Actually I blame Indigo. I never had this problem before they merged. *glare*