Enterprise Rent a Car Flight Information Requirements

It would be my first time personally renting a car from Enterprise. I opened a new user account on the website and created my reservation. They sent me an e-mail to check in 1 day before the rental. (It's like I'm buying a plane ticket.) I completed my check-in process. I received an email that my reservation was completed. It's a 6 page one. PDF file. When I arrived at the Enterprise office to pick up the vehicle, they told me that they could not deliver the vehicle if I did not have a flight ticket for my first car rental. 4 of us, with our suitcases in hand, arrived at Istanbul airport at 9 pm and this is the view we encountered. While I was trying to explain my problem in the office, I continued to be stubbornly rejected. Look, I paid for the car's rental and insurance at the time of booking. There is no problem with that. They insisted not to give the car. Since you have such a rule. It is obvious that I am new to your system. You have all the information on my driver's license. Why is it "flight information is required for the first rental" when I press the complete reservation button? Didn't I get a warning? How do I know this rule exactly, brother? Will revelation from Allah come to me? When I checked again later, among all the things to pay attention to during the reservation, there was only a small box: "I Want to Write Flight Information." It is not stated that it is mandatory and it is left to me whether to enter or not. And the insurance options you should pay attention to when renting a car are sandwiched between the address and payment information. Also, at the bottom of the 2nd page of the 6-page PDF they sent after the reservation, written in small print and tucked in between, were the words "We kindly request you to send your flight information." There is a phrase: This is complete nonsense. They gave us a vehicle that night. Other companies had no vehicles left because it was New Year's Eve. I am a victim and the only culprits are the managers who set such a crucial rule and try to hide it, and the employees who do not understand the problem.