Challenging Experience with Turkish Airlines on My Flight

I arrived hours early for my flight on 10.06.2024. I tried to check in more than 2 hours before the flight, but I kept getting a 'This page can't be reached' error. I tried using the link sent by customer service, but it still didn't work. Then, I tried the kiosk machine, which displayed 'Seats are full, seek assistance'. I asked a staff member who directed me to Area E, where I waited for 15-20 minutes. I explained my situation to another passing staff member, who told me I was waiting in the wrong place and directed me to D44. I still had an hour left. I got my ticket and rushed to the gate, only to be told that my ticket had been sold because I hadn't checked in and that I was now on the standby list. Of course, there were no empty seats, and I wasn't allowed on the plane. After arguing with the staff, they took me and another person somewhere else and arranged a flight for us at 16:05, giving us a complimentary round-trip ticket and a Burger King meal. We had no choice but to accept. We thought, 'There's nothing we can do,' and started waiting for the plane. Guess what? Our flight was delayed by 1 hour and 50 minutes! I never expected to be so inconvenienced by Turkish Airlines. We pay money, yet our seats are sold to others. At the initial boarding area, there was another person whose boarding pass indicated that he missed the previous flight and our seats were sold to him! They cover one mistake with another. Unfortunately, the staff is very disrespectful. I said I didn't want to use my phone for check-in, and they told me to use a computer. I said I didn't want to use a computer, maybe I don't like technology, and they replied, 'It's 2024'. We had a really bad experience. Turkish Airlines is done for me and my circle. I will complain to Consumer Rights and continue my notifications on social media. Solving problems by selling someone else's seat to another person is just typical of you. You are a very poor organization.