Q: I booked a prepaid, nonrefundable rental car through Hotwire. Then, a few days later I booked another car for the same dates by mistake. I tried to cancel one of the bookings and request a refund.

When Robert Sharp accidentally makes two nonrefundable car rental reservations on Hotwire, he assumes the company will cancel one for him. But it doesn’t. Can he drive two cars at once? Q. I booked a ...