Sorry guys, we were tweaking out a new queue scheme after guys complained about waiting for too long.
At the moment overflow is going to standy operators after 30 seconds, but for some reason it diverting to voicemail if all operators are busy instead of waiting in the queue.
We will revert back to the previous setting.
maybe to prevent such threads or complaints from occurring in the future, you should post some form of a notice on the webafrica website and myadsl forums.
In regards to your question, you will have to have the Usage Notifications option enabled to receive smses. As, you will receive the notifications every say 500mb's downloaded, which then gives you indication as to when your account has/is topped up.