Wow, so all this was happening circa 2006?
The two primary causes for this situation was that the sole wireline telecomms company in SA and there were only 2 undersea data cables connecting SA (and I think Africa) to the rest of the world. Telkom was semi-private and state-owned so they had no incentive to improve things and also had to pay through the nose for access to the two undersea cables.
However, things started to improve when more undersea cables got laid down (lowering bandwidth prices and improving international bandwidth) and the government started lowering entry barriers so that Telkom stopped being such a monopoly.