Account is paid up. Nedbank says I'm still owing

In 2008 I was put under administration for my debt. The was a garnishee order on my payslip that was paid every month. Last year February 2015 the last payment went off. But since November 2015 I've been querying Nedbank Retail recoveries why the account is not taken off as it is paid up. I did send them all the documents they want and than they just say I must wait 21 days. Yesterday I was told that every time you query it the 21days starts all over. This people is hold me back and I can't move forward with my plans.