Turkish Airlines Flexible Ticket Cancellation Issue and Refund Request

I purchased a fully flexible round-trip ticket for Istanbul-Bogota-Istanbul and wanted to cancel the return ticket scheduled for August 8th. Despite having ample time and a fully flexible ticket, customer service informed me that I could not get a refund. They claim that the ticket is not marked as fully flexible in their system. On what basis is this being said? I paid extra for a fully flexible ticket to have the right to cancel and get a full refund at any time. Why can't I use this right now?! Different things are said when purchasing the ticket and when requesting a refund. I specifically bought a fully flexible ticket to avoid delays due to my work. I am being inconvenienced by the ticket I bought trusting THY's assurance. I want my money refunded to my account as soon as possible. Despite explaining my issue for 20 minutes, no solution was offered. I spoke with a lady named s** from THY customer service. My ticket code is "2352191311494". I request an urgent response, the cancellation of my ticket, and the refund of my money to my account.
