Vodacom keep telling me their system doesn't want to do the upgrade

I phoned vodacom about a week ago regarding the premature cancellation because I wanted to go on a cheaper contract and they told me they can work something out so that I go on a little bit cheaper contract because my upgrade date is not that far away.then I received no feedback or no confirmation regarding this.I phoned a couple of time and everytime they tell me the system doesn't want to take the upgrade and they are waiting for feedback from their IT department.If I didn't call I would not have known that there is a problem with their system.If the IT department takes about a week without any feedback I don't know if this will even happen this year otherwise it would have been solved already.If this is not resolved before the 1st of December I am going to have to change to another provider.this is very bad service.