Failure to close account leading to poor credit report

I changed an ABSA account online in August, and somehow another account was opened in my name. I went into the branch to sort out the issue, where the consultant assured me that they will close the extra account and change my existing account as I initially wanted to do.

However a recent credit report revealed that the account is still active, and that the last few months worth of bank charges have been accumulating, leading to a default on my credit score. This is affecting my ability to get a home loan and is very upsetting.

This is unacceptable. I went into the branch to close the account, and they did not complete the transaction. I was not notified even once per phone, sms, mail or email that there is account in arrears. This could have been cleared up months ago before it affected my credit score.