Telkom Cancellation Horror

TELKOM ACCOUNT NO: *** - I cancelled my Telkom service in Oct 2019. I am now receiving letters from Debt Collector NuDebt ***), to pay outstanding fees. According to them, I have been on a 24 months contract with Telkom, which I did not know about, and the account is not showing such information. I received a printout of 171 pages from Jan 2016 to Aug 2020 detailing all subscriptions and costs. I worked through the printout and accordingly found from pages 150 to 155 the time frame of my cancellation, which ended in a credit amount due to me at the end of December 2019. Then on page 156, Jan 2020, they commence the account with a wrong opening balance, and the calculations continue from there-on to Aug 2020. Now they demand the amount of R 1638-71, or I will be blacklisted. We went from the credit due to me, now to demand due to them—a totally ridiculous accounting system. If you look at dates for 24-month contracts, this also does not make sense. Commence Jan 2016 ends Dec 2018, commence Jan 2018 ends Dec 2019. So the last page, as per printout, should be page 155. They went on and debited me after my cancellation period: all in writing and numerous e-mails. Please assist in getting this sorted.