Take a look at the network status page. My tower has been down for a while but seems to be back up. It's currently slow as fu*k! The connection link is sitting on 0k
See Incidents:
03/07/05 Base station maintenance 03/07/05 Johannesburg and Pretoria iBurst subscribers INFORMATIVE INFORMATIVE
Details Base station maintenance has been scheduled between 10:00am and 12:00pm. Each base station may experience up to 30 minutes intermittent connectivity.