Hidden Cost at Booking.com

The site is efficient and works well however they added a 10% city surcharge onto my account without notifying me. They advertised a night stay in Stellenbosch at R 992 but charges and took R 1079.02 . . I did not see any notification on the site that there was a 10% City charge and it should be included in a detailed breakdown before paying. Also if I cancel the booking I only get R992 back. Seems there is a **** going on here.