I booked a car thru their web site, and now United cancelled my flight so I will not be needing a car. So I tried and cancel using their web site and it errors out trying to cancel. There is not a phone number to call for customer support or service so I can make sure that they got my cancellation. I called AVIS who the reservation is thru and they tell me that I have to cancel thru Rentalcars.com and they can't cancel my car rental. What the heck. This is a racket to make money. I will not use Rentalcars.com or AVIS again