Dollar Car rentals is just a non existing company in Oslo central station, nobody knows about it (station information, even Hertz employees from which I was supposed to get the car, the reservation was not in their system). So I lost one day and never get the car, then had to go to the airport to get a car from another company. I don't know if it's a scam or just a bad synchronization between dollar and kayak systems, but NEVER RENT FROM DOLLAR IN OSLO.