It gets funnier. The loss leader was one per customer. The guy actually argued that because he had gotten the refund and was given the original for free, it didn't count as a sale and he was still entitled to buy the "one per customer".

We had to pick up the phone and start "calling the police" to get him out of the store. He lectured us on how there was no way we could stay in business by refusing to accept people's money.

There are some days I wonder if all humans are sentient.