an account that was paid up and closed.

I paid up and account of Markham during May 2015 and requested the account be closed and I was sent a letter confirming the account was closed and paid up. During Nov 2015 I requested my credit report as I was planning on buying a house and was declined by all banks and to my surprise the account was still open and was showing I was in areas of about R60, even months after I paid up the account and requested same to be closed, till today they promise to get back to me within 21 days but still the account is showing its open and in areas when doing credit checks.