Booking.com Incomplete Reimbursement for Canceled Reservation

On July 11th, my spouse, under the Booking account, made a reservation at a hotel in Antalya. The reservation number is 4308828***. We canceled the reservation within 30 minutes and decided on another hotel. The email my spouse received stated that 1005 euros would be refunded, but a lesser amount was credited to our account. The nature of the deducted amount is also unknown. We received 2500 TL less than the expected amount, and I fail to comprehend how a company like Booking could allow this. The reservation terms also indicated a zero-refund policy for cancellations.