Munnik Basson Dagama Incorporated harassment

I have been harassed by MBD (Munnik Basson Dagama Incorporated). I get numerous calls from them with different numbers. When you call back the line goes dead, Their staff also work from home and they all call from different cellphone numbers. They do not communicate with each other and then you receive calls all the time. A payment arrangement was made with them which I have paid every month. Nevertheless I still get harassed at 7h00 in the morning continuously. All these calls and sms's they add to their costs on my account i.o.w. they make money by just calling and not even answering the phone. I have complained about them on numerous occasions and even called Standard Bank to report them. I have also seen numerous posts about other people being harassed by them including a **** that was reported stating that he person owes money and they need to pay not to be blacklisted . The following numbers they call from is *** and *** with the last digits that changes so a person can not block them either. They also harass my father in which case he has nothing to do with it. To me, this is ********.