Turkish Airlines Rescheduled My Flight and Provided Poor Customer Service

I purchased a ticket from THY for a trip to Italy and a return from Amsterdam. A month later, I received an email and a message informing me of a change in my flight schedule. They mentioned that I could either cancel or make a free change. I called to ask how long this offer was valid, and I was told over the phone that there was no specific deadline and I could use it until the last day. Two days ago, I called to make a change with ten days left before my flight, but I was told I had no such right. I emailed customer service, forwarding the messages and emails I had received, and provided the date of the phone call. I asked them to urgently resolve the situation. Today, I received a response stating that ticket cancellations or changes could only be made according to the fare conditions of the purchased ticket. The fare conditions vary depending on whether the ticket is flexible, restricted, or promotional. They advised me to carefully review the rights provided by the ticket during the reservation process to avoid similar issues in future flights. I can't hide my astonishment at this situation, as I feel like I received an automated response unrelated to what I explained. I had faced a similar issue with my flight to America in July 2023 and received another negative response. I suffered a loss of ₺100,000. This is not how Turkey's best brand should operate. Such issues did not occur during Mr. K***'s time, and real customer satisfaction was achieved.