Hmm... yup, seems like OC have pulled out locally. Isover now seem to have taken over locally
http://www.isover.co.za. Look at the glasswool ranges.
Subsonic acoustics (acousticpanels.co.za) seem to do all the usual types of things you expect from an acoustics company - along the line of Auralex, so their Mellosorbers should work too.