I have not ever opened/subscribed to a Telkom contract,but I am being handed over to their debt collectors

I have not ever opened/subscribed to a Telkom contract,but I am being handed over to their debt collectors.I once got a call from Telkom asking me if I have app**** for a contract and I told them that I have not and that that person is doing ***** with my personal information.The call center agent said he will stop this immediately.Few months later I receive a sms saying I am owing Telkom and I have been handed over to a debt collection company called Nu debt.I went to a Telkom shop to complain and I was given an email address to email an affidavit stating that I have never opened a contract with Telkom and send my ID also which I compiled with.A few months later I went to a different shop and I was told everything is cleared that account is closed.My current challenge is that the Debt collection company is calling me and sending me massages demanding me to pay this debt but on the other side Telkom tells me the issue has been resolved.In the near future I would like to buy a house and car and my worry is that this whole situation is going to affect my excellent credit rating negatively because of Telkom's weak *****/risk detection tools.All I need is Telkom to clear me from all their debt collection companies and to make sure that this whole situation doesn't have any negative effect on my excellent credit rating.The below is the account which Telkom claim I owe- Telkom acc ***