Once you have chosen the car insurer with whom you would be comfortable to buy car insurance in South Africa and the other nitty-gritty aspects sorted out collect the car insurance policy and read it line by line and try to understand each and every clause.
If you are in doubt refer back to them or someone known to you and knowledgeable in car insurance in South Africa so that you know exactly what you are getting for the premiums you would be called upon to pay, and when satisfied sign and return.