Telkom *** - Paid Up Letter Request - Invoice ***

I had a telkom account in 2012, I acknowledge that it had an outstanding balance, however I never received any call from any collection company ever since. In October, Telkom listed my account on my ITC, when I learnt this I made contact with them. I then requested an invoice so I can pay whatever amount is outstanding, I got a run around every urgent telling me that the account is closed and they cannot pick up the collection company that collects outstanding debt for Telkom, they will however escalate the issue to the team leaders. There has been no response to date until I one of the consultant sent me the last invoice they have and I have since paid the invoice. however I still cannot get paid up letter so I can de-list this debt on my name. I have sent emails and called, but they just not interested. Can I please get assistance as I am now unable to obtain any credit due to Telkom's inefficiencies.