Turkish Airlines Refund Delay Issue

While waiting for my Turkish Airlines flight, I was offered a deal by the airport officials. They proposed that I take the next flight in exchange for 100 €. I accepted, and it was stated that the money would be given in cash at my destination. After the journey, when I inquired, they said they would deposit it onto my card as they had no cash available. They requested several documents, which I submitted through the official page. Despite more than a month passing, neither my money has been deposited nor any action taken. Speaking with customer service daily and seeing them blatantly ignore their duties is another issue. They are now at a point where they hang up the phone on you. What I want to say is that they neither do their job nor understand customer service. I will also file a complaint with the necessary authorities.