SAA Express cancels flight

I had a return flight on SAA (Express!) PE-Durban. On the return from Durban to PE, I was called the evening before the flight to notify me that my flight was canceled, but that I could take the next flight back to PE. Now, the reason I booked SAA, which was R800 more expensive than the other air lines, was because of the time schedule that suited me best. So, I booked my air tickets at SAA for the convenience of the time, and then they canceled it! On my request to the staff at the Durban airport, they told me that they had a shortage of aircrafts! Just to learn from their manager a few minutes later that the cancelation was due to the fact that there were only 10 seats booked on the original flight and therefore they canceled this flight and rebooked those 10 passengers for the next flight. They offered to let my fly via Jhb to arrive 35 minutes earlier - which I declined for not wanting to sit on aeroplanes for the whole morning! The end result: I had to cancel my afternoon meetings and take a much later flight. I thought SAA is pulling up it's socks... not!