CellC and NuDebt are *******

Cell C handed me over to Nudebt . I have been sending them responses to their emails of handing me over and final demands for almost a year now but they refuse to look at my emails. Cell C sent me 2 statements for the same account. It took a few months and I thought it was resolved but then suddenly Nudebt contacted me. I have sent both the statements showing them the problem but neither does CellC or Nudebt want to help resolve this. How can I blindly pay ? They have been harassing me with calls for over a year now and in all this time only 2 or 3 times did they respond but as soon as I send my proof they don't respond and promptly send me another demand. They keep adding interest. I emailed CellC themselves directly in the hope they will understand but they also are not interested. From around R700 the bill is now around R1500. Today Nudebt sent me a mail saying that Cell C said they must go ahead with the demand and that I have 3 days and that interest charges have not been added so u can't understand how it went to that amount. I have all our correspondence but aside from their demands , very little actual correspondence from both them and Cell C. To me it seems like this is pure ******ion. How can a large company like Cell C be so incapable of wanting to resolve a problem. I read some reviews about NuDebt and it seems this is how they operate. They never resolve any disputes. They just want the money.