I Experienced Inconvenience Due To Misinformation by Turkish Airlines About Ticketing

I called Turkish Airlines customer service to arrange my flight ticket from Istanbul to Sirnak on October 27, returning on November 2. I wanted to change the ticket to Mardin. During the process, the outbound flight was ₺700 and the return flight was ₺500. I asked customer service if I could cancel the ticket and rebook it. They said yes. I insisted and mentioned that I wanted to cancel the ticket. They confirmed. After canceling the ticket, I asked about the new prices. They said it would be ₺1650 from Istanbul to Mardin and ₺1300 from Mardin to Istanbul. They mentioned that the seats might have been filled. However, during the arrangement, these prices were not shown. As a result of the incorrect information from Turkish Airlines, I incurred a loss of ₺1200 and became very frustrated. I urgently need assistance and expect a prompt response. Ticket number V8M6DG. Z****** A***. 0530*****59.