My parents who are in their seventies, retired, and on Social Security stopped at Walmart on US Hwy 80 in Mesquite, TX to get gas. After paying at the pump with a Walmart Gift Card and retrieving the receipt, the woman in the booth comes over the speaker and asks him how he intends to pay. My Dad tells her he has already paid and shows her the receipt through the window. They argue a bit, then she asks him to see the $500 Walmart Gift Card. Instead of telling her to buzz off, he hands her the card. She...