Try Afrishox, I know they import Bilsteins, thet can be re-valved, so much cheaper to fix than replacing again.
42 Richards Street, Selby, Johannesburg, South Africa
GPS co-ordinates: 26° 13′ 2″ S 28° 2′ 13″ E
tel: +27 11 493 5730
fax: +27 11 493 0500