Turkcell Adplus SME Service Hasn’t Refunded My ₺22,500 After 1.5 Years

I bought the Turkcell Adplus SME service for my business and paid ₺22,500 with my credit card. I decided to cancel and sent the return invoice like I was supposed to, but getting the refund has been a real hassle. I’ve been working on this problem for more than two months now, and I keep running into delays and getting shuffled around between different people. Even though they finally said they would handle the refund, I still haven't seen any payment come through. It's been a year and a half, and I still haven't gotten my money back. I’ve put a lot of time and effort into this, and now I just feel disappointed with how Turkcell has dealt with it. Can you please get this refund processed right away?