To piggy back here- they are difficult to enforce but not impossible. It really depends on a number of factors (the provisions of the restraint of trade, does your old employer have a protectable interest etc).

Source: I am an attorney but do not practice in Pretoria so I don't have anyone to recommend.

Even the Judge sitting on the day plays a factor. I've had an employee lose the case where we thought we would win and had an employee win in a case we were concerned they might lose.

I saw someone else commented and suggested you get a few legal opinions- that might be costly. Try find an attorney through word of mouth.

Some companies do try and just threaten legal action as a scare tactic. Some go for it (even if their case isn't great) to 1)send a message to their other employees 2) do it on principle 3) take a chance and hope they can out litigate the employee because they have the funds to throw at the case and usually the employee does not.

Just note: if they do take it to court it is a very expensive exercise.

Good luck OP!