Not willing to assist in a legal matter I am wrongfully being accused of

MTN handed me over to Hammond Pole for an amount that I do not owe them. I have been telling Hammond Pole that I am in the process of trying to sort the matter out with MTN (although it has been taking months, because MTN is even more useless and unwilling to rectify their issue). The staff at Hammond Pole have been rude, arrogant and completely unwilling to listen to my explanation of the situation. Every time I speak to them, a different person tells me about something else I should do to try and sort it out. Or they say they will escalate it and get back to me (yeah right)... I won't hold my breath. I get messages and phone calls numerous times a week even though we would have agreed on a course of action the day before. (like them escalating the issue for investigation or me going to get a sworn avadavat, etc) Nothing helps, I still get threats multiple times a week! Is there no more service delivery in SA?? Nobody willing to do their job to the utmost to sort these matters out?? After reading more reviews on this company, they also clearly don't respond to any customer issues. I'm so tired and stressed about this issue. Never EVER have I not honoured my debt. In fact, I don't make debt. My phone is the only account I have. Yet, I am spoken to as though I am a ***** ******** by the staff of this company. I'm fed up.