*********** Staff not doing their jobs resulting in a bad dedt against my name

I don't even want to give one star, more like Negative , I emailed Vodacom 2 Years ago to give them notice and close my data contract which I had not used in over 5 years as I lost my simm and when trying to get a new one just gave up as it was impossible. about a year ago I was contacted by a debt collector stating I owed Vodacom money as my ABSA account had been closed and my Debit order was rejecting after which I resent all the proof of me requesting the closure of my account and explaining that I would be closing my ASBSA account, another few months went by and another debt collector contacted me , I then again sent all the email proof and they said they would look into it, another year later FNB reflects under my credit rating me as a bad payer stating I owe Vodacom Money, again I email and send proof only to here now that the account was not closed and I should have got an reference for the account closure, at no stage over the last 2 Years as anyone ever mentioned this, now they wanting me to pay all the arrears as they did not inform me or correspond with me on what the correct procedure is to follow, knowing full well that in the last 6 to 7 years I have not used this account at all