Can't upgrade or speak to customer acquisitions

I have 5 contracts with Vodacom, 4 of which are for smart phones. I have been told I cannot upgrade any of them to a smartphone because my profile rating is low due to a negative account on my credit report. This despite the accounts being in credit for almost a year and currently still in credit by over R2000. I have tried repeatedly to speak to Vodacom to find out what, exactly, is causing the issue, and have been passed from pillar to post. The one department that can assist me - customer acquisitions - cannot be contacted, despite a Vodacom consultant telling me I need to speak to them and even putting me through to them. I get to an automated response requesting a code, which I don't have. My account was last reviewed in August 2014 but Vodacom refuse to review it again, at my request. I have tweeted, called, emailed and visited 2 outlets with no-one able to assist. What is the point of having a smart phone contract if I cannot upgrade it? I have been a customer of Nashua Mobile for 15 years without issue. Now that they have been taken over by Vodacom, all I experience is bad service. There go 5 more contracts Vodacom. Cancellation is my only option here.