Most places deliver all over the world, 7leagueboots and Pro-Jump do I believe (might be wrong though)
Most places do not
deliver all over the world. 7 leagues and projump included. There are dealers in a large number of countries but licences, agreements and patent restrictions often stop dealers shipping world wide. Poweriser and 7's are only allowed to sell to their 'patch'. Projump can sell/ship to a number of European countries (but not all).
Best thing to do is find a (local) online dealer. Not many real shops sell them.
I don't know if south africa is covered by the patent or not. I don't know much about getting stilts in countries with the patent but there may be more options for you. If possible avoid skyrunner stilts. For many they are the easiest and cheapest to get hold of but the quality can vary from good to pretty sketchy.