Collection Agents Scam or Not

In September 2014 I recieved a call from RDP collect. that I owed then R30 000 .00 from 9 years ago for an FNB account. I requested statements. After nagging I recieved them. The statement saying 29/04/2008 the account balance was zero. they would speak to manager. For 5 months nothing. Then I get a call again 20 May 15 saying again I owe money. After I explained the whole story and resent statements I got told somebody didn't do something right. They will talk to manager &amp