I'm not familiar with the specific example you're quoting, in terms of what the facts are. I'm not sure I understand the question.
If I go back to the point that you made about the prepaid card, the amount of discount they get will vary depending on how much prepaid balance they have. That's why you get differences.
Certainly, the customer you referred to.... We would be very happy to work with that customer to look at what the issue is. On the most recent example you quoted, as I said, we really want to look into it. If you could provide those details, we will make sure we do the right thing for that customer.