Issues with Turkish Airlines Flight and Seat Selection

THY used to be among the leading airlines worldwide with its services. However, mediocrity in every area has also reflected on THY's services. They are no longer among the top airlines providing the best service globally. Neither the meals they offer nor their services meet global standards! They have continuously lowered the quality of their domestic service to the bottom. They started selling seats for an extra fee, but they are mishandling it. I bought tickets for my family for a Kars to Istanbul flight. While purchasing the tickets, I paid an extra ₺310 for the available business class seats and selected the seats. The ticketing personnel changed the seats from 3F, 3D to 9C, claiming there is no 3D seat on the plane. This means the business class seat I paid for was changed to a regular seat, and they placed six rows between my parents. This is what happens when you hire personnel through favoritism. I found out about this situation by chance when I called. When I told my father to object, he went and got it corrected. Another personnel member did what should have been done from the beginning and assigned seats 3A and 3B. With its personnel and service, THY has become the last airline I would choose. On top of that, the extra headaches they cause are just a bonus.