An on-line upgrade service which doesn't work !

I have been trying to upgrade my phone on line with My Vodacom for almost a week. I go through all the correct process and enter the PIN sent by sms. EVERY TIME I get the following message :Sorry there have been errors<br> <br> Unfortunately we are having technical issues on this page and are working to resolve these as soon as possible. Please try again later.<br> <br> I have also requested assistance using their 'Call Me Back' feature but have had no response to the TWO occasions I have tried this.<br> Maybe MTN has a better service !