Incorrectly listed on Credit Bureau

I have not had an account with Telkom.. not sure where they get my details from . They have listed me on the credit bureau for about +- R3500. I did get a call from the collections agent late last year. I did tell them to investigate or send me a copy of any contract or paper that shows that I signed a contract with Telkom. I did not receive anything but have bern put on ITC. I would like this to be rectified asap. I have found out today as Im in the process of buying a house and the bank informed me that I was listed