Kia Service Blamed My 2023 Kia Stonic Parking Sensor Fault on Accident

I took my 2023 Kia Stonic to Gaziantep Kia Dicle Service for the 10,000 km maintenance and paid about ₺8,000 for it. On the same day the maintenance was done, I noticed that the front parking sensor was working intermittently, so I immediately called the service and customer support to report the issue. The technician and the secretary at the service told me it could be a temporary disconnection after the front bumper removal and reinstallation, and advised me to monitor it for a while. Due to my busy schedule, I couldn’t return to the service for about a month, and during that time, my car had a minor accident while parked. When I later went back for the 20,000 km maintenance, the parking sensor issue was blamed on the accident, and I was charged an additional ₺5,000. However, the accident only caused a slight dent on the sheet metal, and there was no damage or displacement in the plastic cover behind the sensor, yet they claimed the sensor was broken. This problem clearly started after the first maintenance, and I had already reported it at the time. Customer service never responded to my request, and when I followed up, I was told my request had been rejected without any explanation. My car is still under warranty, but the repair was treated as non-warranty, leaving me in a difficult situation. Since the issue began right after the maintenance and I had reported it immediately, I request a refund of the charge for the parking sensor or a free repair.