It's not the fault of Billionaires that they are super rich. Countries need appropriate tax and regulation to ensure they pay their fair share.
Look at Trump, Billionaire, pays zero tax (unconfirmed, but probable). His secretary paid more tax than him in real terms. The tax laws allow rich people to manipulate their personal finances.
Also, most of their wealth is in share ownership of companies, not cold hard cash or physical assets. If you start a company and own 51% of the shares worth $1 million and it becomes a $1 Billion business, you are worth $510 Million dollars. You didn't steal it from anybody. It is created from the investments of other share owners. But you should be paying appropriate amounts of tax on any income and assets you purchase with your wealth.
This is a sticky topic. There are no real facts on either side that can prove what is the best course of action. But demonising a few billionaires is just a distraction. The politicians love distractions. It means they can loot our R1.3 Trillion budget in peace while pointing at Wiese and Whitey Basson and going "look, rich white dudes!".