I received an sms from Vodacom last month (15 May) stating that "The data bundle on (my cell number) is about to run out. Click [URL Removed] or dial *111# to buy a data bundle & save. T&Cs apply~." Looking on the Vodacom website, I had something like 200MB left. I phoned the callcentre and after the usual rigmarole I spoke to a callcentre agent. They saw the same information as I saw on the website and after "checking with their helpdesk", told me that although it appears as if I have data left, the sms can't be wrong and I should buy a bundle to avoid out-of-bundle charges. It all sounded wrong to me, so I didn't buy a bundle and asked for the matter to be escalated. I received an sms that the "Advanced Data Support Team" is looking at my query and that it can take up to 14 days, but to date I have not had any further feedback.
So on 12 June I get another "bundle about to run out" sms and when I check I have just under 300MB (of a 500MB bundle) left. I have logged another call and now it's been handed over to Billing and Admin.
It looks to me like Vodacom is trying to trick me into buying data bundles when it is not required and my complaints are being ignored.