If everyone got old coupons, rebates and refunds there would be no economy because everyone would be getting everything for free. YOU lost it, not the cashier, not the manager, not the companie's CEO. Why should they honor an unvalid coupon for your sake? Cashiers cannot simply over-ride an invalid coupon, they could lose their jobs for things like this. "Credit my account for $60." is pretty harsh. Your the fool if you went back there and bought a different monitor anyways.