Overcharged

I signed my lease in December with a promise to receive a promotional R500 gift card and also have the first month rent free and was told to pay R3500 by their agent as both deposit and admin fee. January when my statement came it said I owed them R5698.22 whereas my rent is R3733, water billed at about R300. When I called the office for enquiries I was told that I owe the admin fee which reflects as paid on the statement. This is a **** of a company. Moving out very soon.