Poor service and inconvenienced

On the 22/01/2015 we made booking of travelling to Cape Town and the agent confirmed that he has done the flights bookings for the dates that were suggested which was that we leave Johannesburg on the 27/02/2015 coming back on the 02/03/2015. On the 26/02/2015 the agent informed us that the are no flights available for the dates we wanted to travel on and he has to move us on the following day. I'm not happy that i was informed a day before i was supposed to travel while the bookings were done in January. How is it possible that you don't see the availability of flights if the booking were done in January but you only realise it in February that the are no available flights for the dates for me i feel he did not do his job which at the end we ended up being inconvenienced and carried extra cost because we had to book for accommodation at our own cost for the Friday we were suppose to travel on.