Turkish Airlines Made Someone Else Sit In the Seat I Paid For

On August 18, 2023, my experience on the flight from Istanbul Sabiha Gökçen to Kayseri was not what I expected, flying can be exciting and convenient, this time,  a bunch of really bad things happened, that made me feel really frustrated, and sad. the trip began with an unplanned wait. We were told at 11:05 PM that our flight to Kayseri would be delayed. What started as a small problem ended up causing us to wait for hours. We, as passengers, ended up waiting for more than an hour outside the airplane and then another hour inside the plane. This long wait made us really impatient and made us wonder why it was taking so long. Because of the delay, I started feeling sick to my stomach and got motion sickness. To make myself more comfortable, I chose seat 5F ahead of time. It's by the window. But when I got on the plane, I found out that someone else had been given the seat I wanted because they had a leg problem. why went through the trouble then? The last was my luggage was broken...Don't you think it's enough for one flight?? yet you offer no compensation!!!