NRP Risk Solutions - threatening and harassing without any proof

I keep getting calls and emails saying i must pay my Nedbank account or they will escalate it. I have asked them for details as i have never had a Nedbank account. The email gives no details, no amounts that are due nothing. when i ask i get told they will get back to me - well that doesnt happen. the one told me to go into Nedbank and find out what account it is - really. i know i dont have a nedbank account why on earth would i go into a Nedbank branch to find out about a non existant account that they cannot even give me information on. I am going to report them to the National Credit Regulator.