Unwelcome agressive sales

Some company based in Durban called me on Friday claiming to be a private company representing vodacom from the number ***. <br> <br> I was harassed by the sales agents for about 30 mins while they tried to agressively sell me data bundles and routers for which I had absolutely no need. <br> <br> The also seemed to have full access to my account information including usage patterns and monthly billing details. They also seemed to have been able to access my information directly from the vodacom system.<br> <br> I find this as an infingment on my privacy and can only wonder why would vodacom freely make this information available to any \Tom