I see this has yet to be answered but I am guessing you already found the answer somewhere.
I am writing this for other users who struggle with the same thing.
The Afrihost Mobile Voice products don't activate immediately. Should you be an MTN user, I've timed it to be about 15 minutes after sign up and
correct procedures followed. With Porting, it takes 48 hours as per porting instructions on our website.
Should we have a problem, this will be notified to clients via our website network page.
Hope this helps someone!