Harrased with calls

I was owing Bonitas the amount of R 1800 + when I terminated my employment with my previous employer, I started paying bonitas monthly and my last payment made was on the 14 December 2015, Since the begining of February I have been receiving calls from the company Credit Worx apoke to Mbali and Gugu advising me that I owe them the amount of R 1300+ and I have been handed over to them by Bonitas, I have been sending email to them to assist and they never responded, I soke with different consultant rom the credit department which they never assist me ( Pesana, Mandy, others) I then called again the last time I spoke to Solakhe Nobamba, he did help me with the investigation and advise that I dont owe them, but he told me that I'm the one who supose top call the attorneys and gave the attorneys details, which I advise him that Im not going to call nor email the lawyers it is their duty to do that on their side, attorney details as follows (For the removal your name on the Credit Worx kindly call Bonitas lawyers on *** or *** and [Email Removed] I still receive sms and calls from Credit Worx advising me that I owe them. No one is prepared to handle this.