Turkish Airlines Seat Change Issue on Purchased Tickets

On 15.08.2023, I purchased tickets and seats for my spouse and me on the THY website for a flight from Ankara to Bodrum Milas on 01.09.2023. We did the same for our return flight from Bodrum Milas to Ankara on 04.09.2023. Attached are screenshots of the emails sent to my spouse.

During check-in, my seat was moved to the very back, while my spouse's seat remained as purchased. I immediately called your customer service. They said they would help, but to no avail. We had to fly that way. The same thing happened on the return flight. Again, my seat was moved to the back while my spouse's seat remained unchanged. This time, when we called customer service, they clearly stated they couldn't do anything and advised us to provide feedback.

My spouse had to move to the back where I was seated. For this, I was charged an additional ₺70 for a check-in I had already completed.

There was no warning, no explanation. The customer service made up excuses like operational issues, plane changes, or plane consolidations. By what right can you cancel the seats we purchased and then charge us again?

I am curious to see how you will explain this injustice and how you plan to compensate us.

N***** h. A**