Carlos, a resident of Chicago, was on a road trip to California when he heard a noise under the hood of his car. He took the car to a mechanic for repair. The mechanic overhauled the power steering unit and billed Carlos $600, which he charged on his credit card. Later that dayCarlos having driven about fifty milesthe car made the same noise, and Carlos took it to another mechanic, who diagnosed the problem as a loose exhaust pipe connection at the manifold. Carlos was billed $300 for this repair, with which he was satisfied. Carlos returned to Chicago and examined his credit card statement. What rights has he as to the $600 charge on his card?