Nedbank not owning up for their negligence in opening of credit card on my name

I've been handed over to Nedbank's debt collection agent for a American Express credit card that I have never received nor used for transactions. This was apparently opened in Dec 2014. Moreover, this account reflects negatively on my credit profile with various credit bureaus.

I've called in Nedbank customer care line several times from Feb 2018 till now trying to get this resolved, but I seem to be hitting a brick wall. The feedback I received from this one consultant was that this is an error on Nedbank' side and he assured me that this would be resolved within 7 to 14 working days with all relevant credit bureaus being notified to update my profile accordingly but clearly this hasn't been than as yet as my profile still appears to be owing Nedbank.

Just today, I've contacted Rossouws (Nedbank Legal Agent) and the feedback received was instruction was received to have my file closed and this has been done accordingly.

My question is why my name hasn't been cleared with the credit bureaus ?? What's taking so long?? This is holding my life back!!