Harassment for money \owed\""

I registered my son in 2009 at vuselela jouberton for N3, but they registered him for NCV instead without us knowing. A week later we noticed and went to rectify the registration back to N3. He then proceeded to do his N3 subjects and write the exams. In order to write the exam, there should be no outstanding fees, therefor no money was owed at the time of the exam.Despite this, I keep receiving letters from VeriCred Collections that I owe Vuselela Money for the amount of R1201,99. I have gone several times to try and sort it out and have been told by Vuselela that it has been rectified. I then later once again receive a letter from VeriCred that I owe money. I have phoned them multiple times to sort it out AGAIN just to be told they will sort it out and phone me back, but they never do. This has been going on since 2009.I don't know if Vuselela is trying to charge me for the NCV course that my son never did? When I try and phone VeriCred nobody picks up the phone and when they finally do they put the phone down in my ear. My husband now gets sms's from VeriCred that we owe money.We are tired of being constantly harassed.This needs to be sorted out immediately and permanently.