Turkish Airlines Flight Schedule Change Issue

I purchased a flight ticket from Turkish Airlines for the dates November 23-27, 2024 with PNR UP3RN6. Due to a change in the flight time on November 23, I wanted to change the time of my flight on November 27 to the evening. However, the online application gave an error, so I called the Turkish Airlines customer service at 0 (850) 333 08 49 to make the change. They confirmed the time change for the flight on November 23 without asking about the other flight. Since I was using the automated system, I couldn't make changes to my other flight and ended up confirming it. I immediately realized the issue and called customer service, but they said they couldn't help. My friend had successfully changed both departure and return tickets by speaking to customer service. When I called again to explain the mistake, they said I could only make changes for a fee since I had already confirmed. This situation has been very upsetting for the holiday plans I made with my friends. It seems Turkish Airlines does not value customer satisfaction and is unhelpful in case of mistakes. It's interesting that a company with such strict rules could have any customer satisfaction at all. They are aware of customers being in a difficult situation but choose not to help.