Unfairly credit listed

Good day I am being treated completely unfairly about debt that I do not even believe is mine and charged a interest rate that is completely ******** by MCS Debt recovery. ***) They are trying to collect from me for Telkom. I had an account years ago that I paid in full. I moved and years later contacted by MCS Debt recovery telling me that I owe an outstanding amount. Unfortunately I can’t prove I was paid in full as I changed banks. My problem is in the years that they tried unsuccessfully to contact me a lot of interest was added to my account. They say I owe almost R3000 now and I see what was outstanding was just over R800.00 The person that I deal with is Kobash. I would like her and MCS debt recovery to be investigated as the interest charged cannot be in accordance with the law. The company constantly try to get me to pay. When I asked them to explain all the interest they say they will investigate. They then don’t follow up and then when they call again a month or two later same thing happens that there are more interest and they can’t explain the interest. Every time it is the same, they will investigate and when I ask them what is happening they are investigating on their side and while they do that I keep on accumulating interest. This matter has me credit listed and I cannot purchase a house. The company offer not help or assistance and they just keep on charging me. I am at a loss for words and don’t know where to turn? Regards Franz Van Rooyen *** ***