Booking.com Overcharged Me After Cancellation of Reservation and Didn't Refund

On August 2nd, I made a hotel reservation in Greece through Booking.com with my QNB Finansbank credit card, choosing an option with free reservation and cancellation. Later, I canceled the reservation. Although the payment was supposed to be 83 euros, 123 euros were charged to my credit card. When I contacted the bank to ask where the charge came from, they told me they couldn't access that information. I tried to reach the hotel through Booking.com, but I don't know how to resolve the issue or how to get my money back. Moreover, my bank can't see the authorization code or other details and can't cancel the transaction either. Confirmation number: 4811.242.619.


