Volkswagen Passat Higline Clutching Problem

I have been using a Volkswagen Passat Highline since 2021 and have been facing a clutch problem. The car is still under warranty until the 15th of 2025, but 'Gökmen Otomotiv', the authorized service center, asked for ₺55,000 to fix it. The issue started after they performed heavy maintenance when the car reached 120,000 km. Before that service, the vehicle had no such problem and was running smoothly. I even contacted customer support, but they redirected me back to the same service center without offering any real solution. I visited them again yesterday, but they still demanded ₺55,000 for the repair. This should be covered under warranty, as it is not a user-related issue. I am filing a complaint against Gökmen Otomotiv and Doğuş Otomotiv.