Air Canada sold me a ticket that couldn't possibly work, treated me badly, and cost me two days, and then they refused to compensate me (there's way more there that I haven't published, ending with them telling me to get lost). So I filed a complaint with First National Bank of Omaha, the issuer of my VISA card, in late July.
The first-tier customer-support rep who took my call collected very basic information about my complaint and told me that a representative would call. Instead I received a letter a couple weeks later, in mid-August, saying they had investigated my claim but, since Air Canada had transported me, albeit badly, there was nothing they could do. I called the person who signed the letter, and our conversation went roughly like this (I'm summarizing slightly):
Me: This is not how your representative said this would go. I'm very disappointed that my case was closed without even talking with me. By the way, I'm a customer of 19 years who's only once before ever asked you for anything.
Her: They did transport you. If you hadn't used the rest of the ticket we could have helped you. You have to take it up with them.
Me: When the problem arose I was stranded in another city. Three times. They had me over a barrel, don't you think? Also, they sold me a ticket that could not possibly work; isn't that at the least misfeasance if not fraud?
Her: I can talk to their bank (instead of the merchant) and try to work something out. Sometimes that works, sometimes it doesn't -- it's basically a professional courtesy. What do you think is fair compensation? A full refund probably isn't going to happen.
Me: They did transport me, as you said, but they messed up my vacation and cost me extra money besides. I think a refund of half the ticket price is fair.
Her: I'll see what I can do. It may take a month.
Today I received a letter saying they have credited me for half the ticket price. The letter says "this is an attempt" and that if the merchant disputes it they will have to charge me again. So now we wait. Let's hope that this bank-to-bank negotiation is usually settled at that level without further interference.