Lost Refunds and Hidden Fees on Turkish Airlines

I am extremely dissatisfied with Turkish Airlines! There were three options available when I bought my ticket. I went with the company that guaranteed free changes and refunds under any circumstances. However, I requested a change the day after purchasing the ticket and well within the allowed time for changes, and they informed me that I would receive a refund of 200TL. Nonetheless, they demanded an additional 40TL as a change fee. Despite the fact that I had paid significantly more for a "free" change, they insisted on this fee. They also stated that I could pick up the refund at the airport on the day of the flight, but when we arrived, the staff refused to issue the refund, claiming that they needed to see the credit card used for payment, despite the fact that this was never mentioned previously. They then assured me that the 200TL refund would be deposited into my bank account. No action was taken after contacting customer service to request that the refund be credited to the payment card. The next day, we reminded them, but nothing happened. We even provided the account holder's IBAN number, but they still did not refund the money. They claimed we had to show the card used for payment at the airport, then said they couldn't refund to that card, and finally asked for the IBAN number, all while failing to process the refund in any way. Turkish Airlines' inconsistent behavior has disappointed and outraged us. Despite multiple phone calls and written feedback, they have not refunded our money. They initially stated that they needed to see the credit card used for payment at the airport, then stated that they couldn't refund to that card and requested the IBAN number. Their incessant excuses are unprofessional. They even suggested that we consider legal action during our last phone call, which shocked us...