Application declined?

I app**** for Private Leisure finance and the application was immediately denied. Since I have a very good credit score and affordability was not an issue either, I was curious as to the reason for the failed application and called the number that was given on the email I received. The lady that assisted me, told me the application was declined due to an arrears on my FNB account! I have never had an FNB account and have never even financed anything through FNB, how can I have an arears? The lady also informed me that she can not give me any further details and I have to contact FNB risk department directly... Can someone please give clarity on this???