Turkish Airlines Flight Delay and Ticket Issue on TK2857

I had a flight with Turkish Airlines on 28.08.2023, flight number TK2857, seat 02C, from Ordu-Giresun Airport to Istanbul Airport scheduled for 14:55. After checking in, I received a message stating that the flight was delayed by 35 minutes. I arrived at the airport gate at 14:50 and tried to print my boarding pass before passing through security, but the system did not process it. When I went inside and approached the counter, they informed me that the plane's doors were closed and it was ready for takeoff. They directed me to other staff members who told me there was nothing they could do as my ticket had been sold to another passenger. They offered to change my ticket to the 03:55 flight for ₺2,700, which I declined. They then mentioned a ₺12 tax refund, which I also declined. This situation feels extremely unfair as the flight was delayed, yet they claimed it was ready for takeoff and sold my ticket to someone else.