Go through your results for flights to Durban in South Africa with Netflights. Although KLM usually has the best prices, it's best to double check what's available for your travel dates.
If these flights are too expensive, try searching for a different time of year. So if your dates are flexible, consider looking at different times of year.
So, if the flights to Durban don't work for you, you could always try searching for flights to other airports in South Africa.
Looking at a few different departure airports will give you even more choice. See what you can find. And remember, it's best to book your flights in advance wherever possible.