Bad service

I had an a chequecurrent account with Standard Bank and on the 24/06/2015 I made a payment of R 6797.59 to settle all monies in arrears. I made an EFT payment from my FNB account and the money cleared the following day on the 25/06/2015. I immediately called standard bank and asked if I could close my account over the phone or if I needed to go to a branch, the person I spoke to advise me that I could close the account. She then proceeded to ask me all the security questions to confirm that indeed she was speaking to the right person. After all the questions were answered she then told me that my current account is no longer in arrears and that it has been closed. My mistake was not making note of her name and the call reference number. A week later, I received an automated voice message saying that my standard bank account is in arrears and that I need to pay an amount of R 800. I called standard bank again and they told me that the account is still active. This is so unfair because now this account will impact negatively on my credit rating. Why do I have to pay for someone else's mistakes?