Account settled but not removed from Transunion

I settled my Cell C Account on 21 July 2014 in full. I sent proof of payment to NuDebt Management and I received a settlement letter. When I did an ITC check in January the amount still reflected on my name. I called Cell C and they referred me back to NuDebt. I called NuDebt and they said the amount still reflects as unpaid. I sent through Proof of payment as well as the settlement letter again to NuDebt and they said they would remove it. I called back a week later and again the same thing happened. I called back 4 times and still I have received no joy. Cell C refuses to update my information with Transunion. I have no idea what to do at this point. As a business owner having this reflect on my name is bad and I don't think that what Cell C and Nudebt is doing is fair. I have tried to call Cell C's legal department 4 times in the space of writing this post and each time I get cut off..... Is this how Cell C is going to continue to treat their clients.