i made the reservation 1 day ago before my holiday . İ pay to trip.com and then an email came from Sixt for confim of the var that i rent. When i went to airport office of the Sixt, the guy told me to pay extra because i have to upgrade of the class of the car. First i Said i don’t want to pay more, he offered me to cancel the booking. İ got angry but (my family with me) i had to say ok and pay 225€ more :( never rent again from Sixt