Unjust Profit and High Deduction by Turkish Airlines

I purchased a ticket through the THY app on November 14, 2023, for a flight from Istanbul to Thessaloniki on November 29, 2023, with a return on December 5, 2023. I made a payment of 5,854.80 TL using my bank card through the same app. Due to work commitments, I had to cancel these flights on November 17, 2023, just three days later. According to the information provided by the app, a refund of 1,288.46 TL was supposed to be processed. Confused, I canceled the flight, expecting this amount to be credited to my account. However, upon checking my account at the time of writing this complaint, I noticed that the promised 1,288.46 TL was nowhere to be found. I cannot comprehend how my 4,556.34 TL disappeared when the cancellation refund should have been 10% of the paid amount plus taxes. How can Turkish Airlines seize this money? What kind of agreement is this? I demand an explanation for this discrepancy and the prompt return of my money. While I can accept reasonable deductions for a ticket purchased and refunded through the app, the exorbitant deduction is entirely unacceptable on my part. As mentioned above, I request the rectification of this error and the immediate refund of my money.