Turkish Airlines Open Ticket Issue

In June 2023, I purchased an international ticket for ₺10,500. Due to the cancellation of my trip, I converted my ticket to an open ticket for an additional ₺3,000 based on the guidance from your call center. I wanted to use my open ticket for another trip. However, for a round-trip ticket priced at ₺15,000 online, I was asked to pay an additional ₺14,500 under various service fees. (I already have an open ticket worth ₺10,500 and paid an extra ₺3,000 to convert it.) Thinking there was a mistake, I asked again and was indeed told that despite all my credits, various service fees were added, and I was asked to pay an amount equivalent to the current online price. I am being forced to process my open ticket through the call center without the option to use it online. Moreover, I do not understand the logic behind being asked to pay an amount equivalent to the new ticket price by charging service fees through four different channels. I request a clear explanation of the legal basis for charging separate fees for each of the three or four service items from the channel I am forced to use. Attached is an image of my ticket. In this situation where I am being victimized for the second time regarding my open ticket, I hope that a global company will not victimize its customers with minor calculations and request that my issue be resolved as soon as possible.