As an owner of many retail stores, customers like the op are not valuable. They are looking to have a policy changed because they are special and are constantly looking for a way to eek a buck out. Rarely worth it.
I got half way through and then could read anymore of the same so decided to through my $0.02 in (sorry if this has been said already).
The customer is always right in the case where if that customer told anyone else the "raw" deal they got at your store would mean that that person would be less likely to shop with you.
It does not apply when if the person told someone what happened and the likely response (as said in this thread a few times) is "man what an ass, that's pretty rude" and does not affect the other persons desire to shop with the store (or could be positive since they want to actually get in on the deal when they are actually valid to)
As the above said some customers are not that bigger loss