Dissatisfied telkom customer.

Good day I had a telkom line that was cancelled 1 year ago. Upon closing the account I was not made aware of any outstanding payments due. 2 weeks ago I received a call from national debt collectors informing me that telkom had handed my account over due to non payment. I asked the consultant if telkom handed over any form of correspondence they had with me prior to this happening. She rep**** no. I sent the debt collectors an email and asked for this information and to date have not received any information from them,yet I'm expected to make payment of over R700 to them. It Is so difficult getting through to telkom. I just need to know what my rights are in this regard.