Vodacom - Very unhelpful with upgrade!

I have a 10gb data contract which I want to upgrade to a 60gb package which is R299 per month. I have been to the data shop and also at another Vodacom store and they cannot upgrade me as there is some sort of profile limit to my name... I have not skipped a payment since I have this contract. The current package is R149 per month and the one I want is R299 per month. I have also phoned Vodacom direct to try and upgrade, but they keep saying that there are no packages available for me to upgrade to! The people I speak to are extremely ill literate and cannot use common sense to help me! They tell me Vodacom declined the upgrade for some unexplainable reason! I have spoken to 6people now and no one can help me! Why is this??? Then I can wait for the contract to finish and just move to another supplier! Bunch of dumb idiots at Vodacom!!!