Vodacom is useless

I had a vodacom account more than, 10 years ago. When I canceled I was never informed that there is an amount outstanding. Now years later they have handed me over for, 20000. My application for telkom has been denied because of this. I have never had any correspondence from them. According to the law the debt it prescribed. I need them to clear this and clear with ITC. I will take this further, no wonder everyone complains about their service and the walk in shops in the pavilion was just as useless. I don't know if they know the debt collectors act but just to educate them any debt that they have not made contact with the debtor in any form is prescribed. I will contact a lawyer if this is not cleared by tomorrow