Ok here is the situation;
Company A in South Africa pays Company B in the USA tons of $$ in order to distribute and license out the content Company B creates. So if you want to get that content in SA you have to pay Company A.
Now what happens with stuff on-line like Netflix, they pay tons of $$ to Company B in order to stream their stuff on-line. But now that only applies in the USA. If Netflix wanted to sell their streaming service in SA they would have to negotiate with Company A in order to do so. Now obviously at the moment Netflix has no desire to set up distribution rights in SA, hence why you are blocked when you try to stream stuff from them.
The same goes for music streaming when it comes to services like Pandora and Rdio.
If that doesn't make sense to you then I just don't know.