Lost all my booking fee

I booked a car rental with First Car Rental on booking.com. I accidentally chose a wrong time, I noticed this a few minutes after booked so I amended the pick-up time and the app showed that the time was amended. I expected an email to show the amended time but I did not receive it so I took a screenshot for the record. When I was getting the documents ready a night before pick-up I noticed that the pick-up time was changed to the initial wrong time. I immediately contacted booking.com. It felt like I was chatting to a chat-bot. They made stupid excuses and blamed me instead. I even asked to send them proof but the person/chat-bot on the other end called Emanuel said that even if I send the proof they will not be able to help me. Needless to say that I did not get any refund non whatsoever. So be careful of this useless platform.