To add - this is not a 1st world country, though fairly well developed. You sound very scared, and I'm saddened by your post...
I think hanging out in the cities would skew your perception a little. Central Durban especially is a bit of a hole - and I imagine you would be spending most of your time near the harbour, which is especially bad. It's a confidence game: look like you know where you're going, don't flash cash or valuables, be vigilant not paranoid. I guess not having transport would make things more difficult as well - Uber is safe, cheap and convenient.
Sure, like anywhere in the world, there are places that a tourist should avoid (around the harbour in Durban, for one

). Hijackings happen, and "knowing better" is not always realistic. We have crime, one of the highest murder rates in the world - and you will meet few people who have not been directly affected by crime of any sort.
But it's not all doom and gloom - and you'll come to realise this for yourself - South Africans are extremely friendly and helpful. It's a case of a very small minority who are spoiling it for everyone else. There is immense poverty here - unemployment is RIFE, and those pigs that are in power are doing their utmost to prevent the situation from improving by lining, nay, stuffing their own pockets. People are fed up, so perhaps there might be a simmering underlying anger as well, that we are ALL feeling. Change is afoot though, so there is hope.
There's some cool stuff to do and see in Durbs:
Kwazulu-Natal Sharks Board (
http://www.shark.co.za/) in Umhlanga
uShaka Marine World (
http://www.ushakamarineworld.co.za/) - bit commercial
One of the best
bunnies in Durban close to the harbour (
https://oflocal.co.za/durban/victory-lounge).
And just you wait until you see the rest of the place...