Turkish Airlines Didn't Refund After Canceling Additional Baggage

I had a flight with Turkish airlines on 15 November 2023 from adb to ist. When I was purchasing my ticket I paid for extra 21kg for check in baggage. Before the flight when I realized I do not need it, I called 4 times them to cancel it. Unfortunately customer representatives are so ignorant, they ca n not even answer in a proper way, forget even solving problems. They just cancelled the extra luggage, then I was told I should contact thy after the flight. I sent them email after the flight. After a week I got reply from them that they investigate the situation and I used my extra luggage. By the way No proof of I used. Just I have to believe their word. So do not purchase any extra luggage from them before flight, they just give you headache and will not refund the money.