NSFAS ****** of the century

I went back to CPUT in 2016 and my bill was R0.00 until today which is R18000.00 awesome. I owe CPUT no problem. I get a call on my work phone from a very rude man saying I owe NSFAS, in turn, I advise I owe CPUT, not NSFAS. I email NSFAS asking for a statement saying I owe them as well as a consent form from me. Instead, NSFAS sends me an SMS threating me of my payment profile that will be damaged. How does it work in SA? Are (NSFAS) allowed to go around threatening people like that with no proof? Is this how the government system works? I need help from anyone or anywhere to help me get to the bottom of this. Are they still chasing the woman they gave 14million to? Somebody Anybody please help me teach these rude people a lesson or two.