Wrong fully listed on paid up account

I`m terribly disappointed by how I find out that I`m black listed on ITC by standard bank with a loan which I paid off last year, I was in a process of purchasing a property & got rejected over something which I paid, If I owe them why didn`t they debit my account to get what I owe to them, there`s no letter of demand or anything of that sort, for heaven`s sake I went to lephalale branch & requested a settlement amount & paid in full, the account in question is: *** which i settled in December now is on ITC as being in arreas, I need account updated as closed & listing removed from ITC as well as the letter so that I can give creditors to proceed with financing me