Turkish Airlines Transferred The Flight To A Third-party Company Without Informing

I had a Turkish Airlines (THY) ticket from Sabiha Gökçen Airport to Basel, Switzerland, on April 26, 2023. Since I didn't have any luggage and I live in Balıkesir, I planned my transportation assuming I wouldn't need to visit the check-in counter. However, I couldn't complete the check-in process via the THY mobile app the day before the flight. I called the call center for this simple issue and learned that my flight had been transferred to Ajet. They provided me with a new PNR to complete the same process on Ajet. When I couldn't complete the process on Ajet's mobile app or website either, I called their call center. They informed me that my flight had been transferred from THY to them, and some of my information hadn't been transferred correctly. Therefore, I had no choice but to check in at the counter before the flight. They neither informed me about the transfer nor took responsibility for the incomplete information transfer. They acted as if I, the passenger, should bear this inconvenience. Due to this last-minute issue, I had to reschedule my ticket to a much earlier time according to public transportation options and ended up going to the airport about 7 hours early. I thought this might happen, and then the journey arrived, but neither THY nor Ajet was present. It turned out that Ajet had transferred the flight to an airline I had never heard of before, SmartLynx, which is not a Turkish brand. I found this out only when I arrived at the gate. I bought the ticket trusting THY's quality based on their advertisements and paid the THY price, but both THY and Ajet transferred the flight to another airline of different quality and profited without moving their planes. THY has become worse than its low-cost competitors in our country. When we want or have to buy a ticket from THY, there is no guarantee that the flight won't be transferred to a third-party airline. I am complaining about THY because I couldn't know which airline I would fly with when purchasing the ticket and experienced stress before the flight.