Turkish Airlines Didn't Pay My Compensation

I had to fly to Cologne instead of Düsseldorf on 06/09 due to overbooking on my THY flight. They promised compensation for this inconvenience. When I went to THY's authorized agencies to collect the compensation, they informed me that there was no cash available and that I would receive an email update. Despite calling and emailing them, I received no response via phone or email, and no one is addressing the issue. When I contacted them through WhatsApp, they claimed that the legal deadline had passed, even though the staff at Cologne Airport had informed me that the compensation was valid for one year. The staff at Istanbul Airport mentioned that I could use a QR code to claim the compensation, but it only led to a feedback page. This is an unacceptable situation for THY.