They are the worst!!! We booked a car rental almost a year ago for this trip and a few months ago had to make some changes to the reservation since we not planning to stay as long. Got to the Fastbreak counter and the person said we don't have a reservation. We pulled up the email to show him, he said both our reservation (initial and modified) was cancelled. No notice by email or phone call. We ask what he can do for us... all he said was to re-book the car rental, but it's super pricey to have to book it right now. That was a different between $140 after tax from our reservation and to book it right now would be close to $200.
If you have to rent a car, go with a different company...