It's a loss, at least as far as your brain is concerned. (Logically, there's no real difference, the fact that it's already technically been incurred is pretty meaningless. (Also, you could argue that since he hadn't paid his credit card bill yet, it wasn't incurred yet.))

Your brain says "this is $11 that I wasn't supposed to spend that they took from me!" That's a loss. You want to get the money you lost due to their mistake back.