I have been working as a Call Center Manager for last four years.
I will not suggest you to develop your call center in South Africa since it’s not well known for outsourcing business.
However, I will suggest you to move such country where you can find the people who have the domain knowledge of this industry since a lot of technicalities are involved to run a call center.
I can understand that you have this domain knowledge but are you confident that if you set up a call center in South Africa, the people you will be dealing with in order to run the business will be equipped to assist you; certainly not.
The best place to move on is either Pakistan or India since they already have a large number of international call centers running smoothly and the supply is not a problem.