Turkish Airlines Ticket Change Issue

I tried to change my ticket for the 6:05 AM Istanbul Airport - Malatya flight at 4:15 AM through the app. I encountered multiple errors. At 4:41 AM, I called customer service, and they informed me that an email needed to be sent to the relevant department to remove the check-in, and after the email, I could make the change with a 300₺ deduction. Despite sending the email, your relevant department could not cancel the check-in, causing my ticket to fall within the last hour's violation and become void. Despite requesting a change for this ticket and creating 50 complaint requests over the past 3 days, I was told it was a user error. I have purchased over 100 tickets from Turkish Airlines and have been flying with them for years. I have never seen such negligence. Normally, I have made this change process multiple times, but now I am being inconvenienced. I will never choose Turkish Airlines again. I will also pursue legal action regarding this matter.