No distribution or transmission system is 100% reliable but failures are infrequent enough for consumes to become complacent. This is that state of play in SA.
There are generation problems mostly caused by economic and political factors. When it is available cheap wind produced energy swamps the market causing generators capable of supplying constant power to drop out of the market or sell much below real cost. The reliable generators have to recoup their cost by charging higher prices when the renewable sourced energy is not available.
SA power prices are high because we are in effect paying for two lots of generation.