Car we wanted to rent was not available

We had reserved a car, when we were checked in a car was not available for at least another 30-45 minutes. We did not want to wait the additional time. The only vehicle available was a truck. The first truck we got there was a low tire. They said that it would take a bit to fix that so they gave us another truck. Having not driven a truck a lot, it took so getting use to. This truck ran great. The shock came when we filled up the tank. It cost $62 to fill it. There was a reason we wanted a car.

How to make sure the vehicle we reserve is available when we get to the rental place.