NBA Making False Claims

I received a phone call from NBA this morning with the usual introduction.....Please note that this call is recorded for ........etc. They claim that I owe Wesbank Finance an amount of +- R 25000-00 due to a personal loan that I received many years ago. I can categorically state that I have never dealt with Wesbank Finance or have ever loaned money from them. I don't know where they get their information from. Also, at the beginning of this year I received a call from Nedbank claiming that I also owe them money from an alleged personal loan, that I am unaware of. I have never heard from them since. I have just this last month settled an outstanding amount owing to Standard Bank through NBA, and am still awaiting a final letter of closure from them. Unless these companies can produce the signed documents and facts of these allegations, I will continue to be angry and rude when they call me with their outrageous claims. Thank you.