Telkom charging me for service / data I never utilised

I took two contracts with Telkom , on for Wifi and the other one for cellular data . The one for wifi reached it expiry date and I owned the router and there was no more monthly data given every month .And that was it . The one for pre paid data also continued and also reached its expiry data and I did not send any indication that I want to renew and they kept on debiting my account and have now been handed over to the attorneys . i had cancelled the account when I called their call centre . The number was not even being used by myself for the past few years and they have confirmed that the data that they have been billing me shows that the data was never used for the past few years.Now why should I pay for the data that I never used and secondly how was i supposed to utilise the data when the number that was initially allocated to myself have now been allocated to someone else . I think its unfair that I be handed over to the attorneys and blacklisted for 1) data that i have never used for the past few years as Telkom themselves confirmed that it has not been used since my contract expired . 2) The cell number that was initially allocated to my contract was assigned to some else years ago and I no longer have access to that number. 3) Why should I pay for services that I never utilised that are linked to the number that was given to someone else. When I called the call centre furious and asked the lady to cancel that contract for me she referred me to a self service option on the Telkom website and informed me how to navigate the website to cancel service which I did . I never kept any reference number as I believed that the case was then closed . Now legal proceedings are taken against me for an exorbitant amount of money for the data I never used for those months and my credit record has been tained . if i had utilised the data and still had access to the number I would understand .