Hostelworld Charged My Card After Reservation Cancellation

I used the Hostelworld app to book a two-night stay for two people from August 7-9, 2023, but due to an error (as shown in the attached video), the reservation was made for one person instead. I paid a deposit of ₺413.49, with the remaining amount to be paid at check-in.

After noticing the error, I confirmed with the hostel that the reservation was incorrect. Just 1 hour and 10 minutes later, with four days left before the stay, I canceled the reservation. While I had already accepted losing the deposit, the hostel charged my card ₺2373.58 six hours after I canceled.

This unauthorized charge is unacceptable, and Hostelworld refuses to refund the money. Charging a canceled reservation is unethical and feels like outright fraud. I demand a full refund of the additional amount charged to my card. Please address this issue immediately.