Booking.com review: Booking.com rental problem

I rented a car from booking. Booking number is 698894515. The car rental company overbooked for that and I just complained about the overbooking issue to booking. I have waited 3 hours for the car but booking cancelled and refunded my reservation “after I picked up the car” without asking me. Also at the rental date I paid 49.14€ for extra protection and it has seperate bill. They sent a mail that they will pay the difference between the cancelled and the new reservation if I prove them with evidence. Since I picked up the car before booking cancelled my reservation, at the return day same company charged me €36,22 more which is 305€. After rental I raised a claim with all evidence (first reservation payment, second reservation receipt, extra protection receipt which I pay at the rental start date (€49.14). However booking keeps insisting on not paying. They believe the rental company. Company told them 305€ contains extra protection amount however I paid it speerately at calrify it with the bill photo. The company that they work with lies and tells the difference is because of extra protection, however I proved that extra protection is paid seperately and I provide evidence photo of the receipt. Then booking told me I passed through tolls, however there is no tolls in the island that I rented. They are acting very unprofessional, unthrustworthy and not protecting their customer.