I would dance like that too if i were robbing the biggest Oil producing country there is.
1- USA prints USD out of thin air.
2- USA buys Oil from SA with those papers.
3- USA sells guns to SA and collect its papers back.
4- USA creates more jobs at gun business.
5- SA sells more Oil to get more USA papers.
Everyone is happy. Trump is a brilliant businessman.
The oil market is "fungible," which means that anyone can buy from anyone. Regardless of established long term trading partners, if someone offers a higher prices, he'll get the business.
You can only trick people who were born yesterday with those lies. Those "various" oil companies are owned directly by the US government. In this situation this puppet company is "Exxon Mobil"
https://en.wikipedia.org/wiki/ExxonMobil
You can't seperate the big companies from the US government because, the US government itself is a big company being run by a businessman.