Kulula tickets

I booked a return ticket from Durban to OR Tambo, Wednesday the 17th returning the 18th. After I booked the ticket my client contacted me and said that he want me on Tuesday at the factory. To change the booking they asked me nearly R 900. A new ticket Tuesday R 430 . When I want my ticket for the flight back to Durban Kulula said there is flight no under my name but I presented the paid booking. I had to buy a new ticket for R 1880 to fly back to Durban. This is totally unacceptable!!!!!!