Garanti BBVA Charged Incorrect Exchange Rate On Credit Card Transaction

On August 15, 2024, I encountered an exchange rate issue while making a transportation purchase with my Garanti Bank Bonus Credit Card. I used my Garanti Bonus credit card to purchase a plane ticket worth $2,207.63 from Qatar Airways' website. On that day, Garanti Bank's USD exchange rate was 34.2240 (see Attachment 1). Therefore, the transaction should have been 2,207.63 * 34.2240 = 75,554 TL. However, 77,483.80 TL was charged for this purchase made with my Garanti Bonus card (see Attachment 2). This corresponds to an exchange rate of 77,483.80 / 2,207.63 = 35.0981 TL per USD, which has never been seen in a bank before. There was a difference of 1,929.80 TL. I contacted Garanti Bank's Customer Communication Center over the phone, and a complaint was filed under the number 5434686. The following day, I called customer service again. I was told that the department in charge of this issue would process the transaction based on the exchange rate on the day it was moved from provisional to posted. This explanation appeared illogical to me. I was expecting the exchange rate on the day of my transaction, August 15, 2024. My transaction was posted on August 16, 2024. Interestingly, the closing USD exchange rate on August 16, 2024 was 34.66 (see Attachment 3). Even at this exchange rate, the transaction should have totaled 34.66 * $2,207.63 = 76,516 TL. I reported the situation again to customer service, and a new complaint was filed under the number 5434686. I do not want such an incident to shake my trust in Garanti Bank. I request that I be notified of this matter via SMS, and that the excess amount charged be refunded. Sincerely,