Not being able to have my overpaid funds paid back

I have logged an email request on the 25th August with Nedbank Debt Counselling department and have had Debt counselor also contact Nedbank. I have fully paid up my account earlier this year and have not been notified that my account is paid up. Due to this I have been over paying during the last 5 months to have accrued over R10,000.00 which Nedbank is ignoring me to pay back. I am not getting replies on my email and nor does my debt counselor. I have fully paid the account and feel it is of the worst service that I still have not received any communication other than a letter from Nedbank stating that they do owe me the money. I need to get my money paid back a.s.a.p. and am not getting any responses from Nedbank. Very bad service!