There are three Xamarin User Groups in South Africa. Here you will find monthly topics which will include both .NET and Xamarin mobile related topics.
The groups are there to bring the Xamarin community together, where knowledge can be shared and experiences learnt from. Hope you see you at an event soon!
Twitter: https://twitter.com/ctxug
https://www.meetup.com/Cape-Town-Xamarin-Users-Group/
Twitter: https://twitter.com/gxugsa
https://www.meetup.com/Gauteng-Xamarin-User-Group
Twitter: https://twitter.com/DXUGSA
https://www.meetup.com/Durban-Xamarin-User-Group/