Hi thavinci,
I am based in a neigboring country Botswana, and we have successfully used VSAT to connect to ISP in itally.
One thing I might add is that your latency will increase using VSAT to connect, and it is not cheaper that using an ISP in RSA. Cost is high, you will be looking at around R10000 per month for a 1mbit download 256upload connection. Whereas ADSL in RSA costs around R500 for the same connection speed, and ADSL obviously has lower latency.
If you still wish to connect to a VSAT provider you can contact bentley-walker via thier website.
http://www.bentley-walker.com
They will be able to let you know if they have a licenced re-seller in South Africa (if they have one in Botswana odds are that they have in RSA as well)
I strongly advise using local ISP using ADSL, as costs are lower, speeds are higher, and you have lower latency, you also have access to using P2P, which is against TOS for most Satellite Providers. (Many ports are blocked on VSAT)
Also there are a couple of days during the year where you will have downtime due to the sun shining on the dish which acts like a solar cooker on your LNB, when the LNB is very hot it shuts itself down or somthing and you will not be able to connect.
We were using VSAT only because ADSL was not available in our area, but as soon as we were able to get ADSL we moved over, and we have had less down time, with greater speeds at lower cost and latency. (We can now play online games whereas VSAT average ping is 600+)
Anyways I hope this has provided you with the required info to make your own desission.