As I recently went through the experience again I thought I would put my tips here for all. I have only used VODACOM as the service provider in fact not VODACOM directly but one of the good franchises. I had tried the 3G stores but they h
ave to sell you a standard sim and then convert wasting time and money. The best option is to get a micro sim activated in store and loaded with data if you are choosing the pay as you use option.
Once the sim is active and data loaded just test it as the ipn settings on the device must be set as must the ability for the sim to use these. This last part is done by contacting VODACOM data who then need the sim number and puk number to do this and it should work in a couple of hours.
Ensure that you know the phone number for the sim and keep it handy, if you need a top-up that is how you will do it. Once again pop into a franchise and buy data if you choose another vendor you will have to find away to convert the data. The franchise shops can immediately load your data. You can also sign up on the VODACOM web site and register the data sim to track usage if you are using in an iPad as yet I have found no other way to see my data usage.
Enjoy.