failure to settle my bill owed by the above company and refusal to send me paid up letter.

I had two accounts with telkom. one had a R-1580.56 which telkom owed me. and the other had R1349.00 which I owed telkom and I was then black listed for this amount.but last week I paid them the full amount I was owing and they promised to send me paid up letter and refund me the R1580.0 they which was due to me. Ref;0 ********** 60071.