Incompetence in handling account

My husband had an account with Incredible Connection for years. In 2013, he came into the Greenacres Store to make a payment, only to find that his card had been cancelled by mistake. He then started receiving letters from Maravedi stating that his account was in arrears so he went to make the payment at FNB. The Greenacres store was aware of the matter. He then cancelled the account to avoid further drama. He received no further mail regarding this account in the past 3years. As far as he was concerned, the account was settled and cancelled. Now, in 2016 in applying for a bond to buy a house, the bank pulls up a credit report stating that he owes Incredible Connection instalments of R2927 for an account 4 months in arrears. The account no. is ***. This whole chain of events began with the incompetence of Incredible Connection in cancelling the card in the first place and having him find an alternative method to pay. If he indeed still owed money after the payment made at FNB, why has he never been informed about it in over 2 years? Can Incredible Connection take some responsibility and confirm that he does not owe any more money. I'm leaving his phone no & ID below.