Not to be trusted! I booked a car rental in Spain through Holiday Cars. The I arrived with my family and young children we were told that the petrol car we chose was NOT available and they said "no problem" we'll give you a Diesel instead. They asked for our credit card for the deposit and only AFTER authorization we noticed 2x as many charges including an expensive "diesel upgrade charge". We complained, did not get a full refund and had Eur 280+ in expenses for late night travel by train and taxi. Holiday Cars would not refund and said this was due to GoldCar as a partner. Don't use Holiday Cars, very poor customer service!