Turkish Airlines Flexible Flight Ticket Cancellation and Refund Issue

THY is not canceling my fully flexible return flight ticket and not refunding the ticket fee. I purchased a fully flexible flight ticket from the THY Sabiha Gökçen Airport sales office, paying twice the normal ticket price, because my return date might change.

Due to a change in my return date, I contacted customer service before the deadline specified on the THY website to request the cancellation of my ticket and a refund of the ticket fee. However, my request was denied, even though the THY sales representative assured me at the time of purchase that the ticket fee would be refunded. This situation has left me at a loss, as I trusted THY's guarantee. I urgently request that my ticket be reviewed, canceled, and the ticket fee refunded to my account.