Failure to close accounts requested

I requested for all my accounts to be closed with Nedbank, i received confirmation all accounts are closed. I am now being told that the one account is actually in fact open, and because the account is a savings account i was supposed to close it at the branch and not over the phone, however the confirmation is another story. This completely the worst banking service i have ever received. Failure to follow instructions, private banking is a complete joke and follow up never takes place unless i lay a complaint