Most expensive rental ever

Booked Cape Town Airport, 7-day rental. Toyota Urban Cruiser (4 of us with luggage). Car was fine. Returned on time with full tank. All good I thought... Had paid Booking.com R3.5K for booking. Blu took another R8K on pickup (I assumed deposit) and another R.5K a few weeks later (card deduction no explanation). So R12K for the weeks rental.. so far Last time I go near this company.