horrible service by the drive through cashier

travelling from Gp to Phongola Kzn hubby and I decided to stop at Mcdonald Ermelo for breakfast. We placed our order on the drive through and hubby made a mistake and trying to correct the order the lady was irritated not sure if it was because hubby had a debit card on his hand coz she just said \ didn't you read the window we only take cash"and we were like why put a sign in the middle of a drive through? She then stormed off to call the manager"