Green Motion Reservation Cancel Without Any Rule

I made a reservation through Yolcu 360 for a rental car from Green Motion. I have an excellent credit score and regularly rent cars from other companies. However, when I arrived at the office, they denied my reservation and canceled it. They explained that despite my high credit score, I could still be rejected. This means that if you want to rent a car from Green Motion, they flip a coin to decide whether or not to rent to you. They have no clear criteria, and it's like they gamble on whether or not to rent to customers. What am I supposed to base my reservation on? I go out of my way to their office trusting my credit score, and not only that, I make plans around the rental. But for no reason given, they probably decided not to rent to me because my credit score was too high for their liking. If you don't have clear criteria, it means you have no business rules. You could reject me based on my name, my hometown, or my appearance. But these criteria should be clearly stated. Your rental policy should include a clause that states that even if your credit score is high, you may still be denied. If you cannot add this rule to your business practices, then you are unfortunately victimizing your customers.