what is the name & model of your dongle ? Some dongles might not have the application software or drivers for Mac OS X.
However you can contact Afric-com call center for support using any of the number(s) below and confirm if your device is capable of working in sync with Apple's Mac OS
Africom from an Africom number - 400
Africom from any network - 0864400
General line - 08644000096
Telone line - 252117/9
Alternatively get another dongle supported by Mac OS X & use your SIM card from afri-com to surf. A good multipurpose device would be the blackberry storm 9530 it support GSM /CDMA & Global Wireless. If i am not mistaken Afri-com uses CDMA for their Wireless WWW access.