I've had a Capital One Cashback card for four months now. The idea is that you're supposed to earn 4% cashback for the first three months you have the card, and 1% thereafter.
When I got my third statement through however, I'd only got the 4% cashback for the third month, and the first two were entirely ignored. I sent them a message about this, and they replied that they were having problems, and it would be fixed for my next statement.
Fourth statement rolls around, and it's still exactly the same amount of 4% cashback earned (plus the 1% earned for that month). I've messaged them again, but I wonder what the chances of me ever seeing the money are.