Turkish Airlines Does Not Give My Overbook Compensation Rights

THY does not grant my overbook compensation rights. I had an overbook with my THY Istanbul-Stockholm flight for two consecutive days on July 31 and August 1, 2023. In return, they gave me two checks for 400 euros each and repeatedly told me that I could get it in cash that same day. Afterward, although I asked several times both at the Istanbul airport and in Sweden, they always replied that we did not have cash. Then they told me to request it to my bank account and they would send it immediately. Exactly 4 months have passed since then, and even though I have created file papers many times, called customer services at least 20 times, and sent all my bank information, they have not given me my right to compensation for 4 months. On November 21, they sent an e-mail saying "As per your request, the fee for your return check number xxx has been refunded" and they did not send any receipt or official document stating that they had sent the money. When I called customer service to confirm, they told me that only 1 check, namely 400 euros, was returned, there was no receipt for it and I had to wait. Even though they knew that there are two checks belonging to the same file and they contacted me accordingly, they only refunded 1 check months later and do not provide any documentation proving that they returned it. Also, they told me that if I overbooked, I could get a refund in euros. Since then, euros have increased a lot and they calculate the amount according to the euro-TL exchange rate of that day. I still didn't receive anything yet. I do not have the slightest trust in THY, which has been making me struggle for months, saying that you will receive your money immediately while an overbook is taking place. I urgently expect you to deposit the 800 euro compensation I am entitled to into my account along with the documents.