Audi Sandton have always refered people to the Audi /VW approved panelbeaters in Wynberg or the chap that fixes chips for them I can't recal the name.
Best is buy the paint from a panelbeater the code is in the sticker in the boot under the matt...get a small tippex type bottle it will cost you around R150 than get online here
http://www.langka.com/ and get the blob eliminator. This is the only sensible DIY way for chips and small marks now if your car has been scratched that is a completely different story....