MTN fails to delink / deregister a number from my name after 2 requests, 6 days

I called custilomer service to block a prepaid MTN number on my secondary cell on 19 Nov 25 (6 days ago) due to the number having been compromised. I was told to go to a MTN shop to delink the number from my id, which I did on 20 Nov 25 at the Galleria Mall shop (5 days ago). I was told MTN does not provide a printout or reference number for delink requests but that I can be rest assured it will be delinked in 24 hours. 5 days later, this number is neither blocked nor delinked. Good thing I don't use MTN on my main cell for banking.