Rentalcars.com Canceled My Booking but Refuses Refund – I Want My Money Back

I booked a 2-day car rental through Rentalcars.com by Booking.com at Izmir Adnan Menderes Airport with Boycar Rent a Car. I received a confirmation email with Reservation No: 791878379, but just two minutes later, I got another message stating that I needed to provide an international flight ticket or my reservation would not be valid.

I was then asked to cancel the booking, but since the car pickup was scheduled for the next day, I was told that no refund would be given. How is this legal? I paid for a service that I was never allowed to use. I demand an immediate refund—Rentalcars.com and Boycar must stop scamming customers like this!