Garanti BBVA Credit Card Usage Fee Dispute

My company is a KOBİ customer of Garanti BBVA bank, with accounts at the Ankara Gimat Branch. Garanti BBVA has charged an ₺850 usage fee to our company credit card, which we rarely use. When I visited the branch on June 27th, four branch staff and one manager refused to take our cancellation/refund request. KOBİ representatives claimed they were not authorized and directed us to a personal account manager, who then referred us to Customer Service. When I called Customer Service, they said they couldn't help and that we should resolve it at the branch. Despite all officials and the manager hearing our conversations, they did not process the request. This process took approximately 45 minutes (which can be verified by cameras). Finally, after expressing my frustration to the manager about their lack of intervention, they reluctantly accepted our written request. Forty-five minutes for a simple request and ₺850 is unacceptable treatment. I have filed a complaint with their customer service, but there has been no follow-up. I am dissatisfied with the Gimat branch officials.