Dollar Rent A Car Charged Me $731 for Unrequested Upgrade on Mercedes E200 Rental

I had a terrible experience with Dollar Car Rental at Atlanta Airport. I rented a Mercedes E200, but when I arrived, the representative informed me that no E200s were available and offered a GLB 250 instead, assuring me it was in the same class. He asked for my credit card to block the deposit, mentioning a fee of $731. I explained that I had already paid through a local company in Istanbul and entered my card details for the deposit. However, when I returned home, I found that I’d been charged $731 for a supposed “car upgrade.” I believe this to be a dishonest charge, as I never agreed to any upgrade fee. Why should I pay an additional $60 per day plus tax for a car change I didn’t request? I advise others to avoid this company. The lack of transparency and the unexpected charges made this experience disappointing.