I regret joining nedbank, its a ****

I happened to close my cheque account with nedbank, the lady on the line assured me that the account is not in arrears and was given a reference. To my surprise, after a week later they called and told me my account was in arrears, I asked how?... they said i accumulated two days after I closed the account. How can a closed account that is closed accumulated intetest or whatever? I gave them the reference number, the date I called them but like they always do, they started denying that they spoke to me on that day. Funny... I was tranfered to another lady who confirmed that she went through the recording and that their agent was on the wrong and they are further investigating they will come back to me. They did not come back to but kept on sending me intimidating messages, then I decided to visit their Malelane branch where I closed the accont for the second time and was also assured that I will no longer have a problem. I still recieve messages and the last one is advising me that the account have been handed to attorneys and a judgement may be passed. This bank is using their bullying tendency on me, they are at fault and they admitted. I have my right to chose which bank I want to bank with, it's like they are bitter that I no longer want to bank with them. But because they a an institution, they do as they please. Where are we suppose to report such conduct?... because I was not advised that if i have a problem I should report them to the bank Ombuds.