REFUND ON ACCOUNT WITH ABSA BANK

I had a cheque account with Absa Bank years ago. I went under debt review in 2010 and paid it every month till 3 months ago when I found out that the account was in a credit of thousands of rand. They never ever try to contact me and notify me that it was being paid up. Since the end of May 2021 I am trying to get them to refund me this money. After hundreds of call and emails with all the documentation nobody can help me OR KNOW HOW TO REFUND me. This is the poorest service I have ever seen nobody knows what they must do and I am still battling to get my refund while they are earning interest on my money.