Credit declined due to old loan

I am appauled by nedbank service and query handling no words to explain other than pathetic. I switched my business bank account to Nedbank and have had a peronal account with nedbank for a while however not my primary account. I have a good credit score yet nedbank and make my payments on time. Whne I app**** for credit on the app, the reasoning stated I my have defaulted on a previous loan.yhe only lain I had with nedbank was back in 2010 and that was closed. So how can I be liable for that loan. I need this removed from my profile as this should not affect me for applying for credit.