NO NOTICE OF NON-EXISTENT ACCOUNT IN ARREARS

My credit score has been crippled due an amount of R9,38 that has apparently been in arrears for more than 180 days. I've only noticed this recently after a pre-qualification request for a home loan was denied, in no way did MTN attempt to contact me to have me settle this miniscule yet VERY IMPORTANT amount of money. All of this while being a pre-paid client, apparently this amount got added to my non-existent account AFTER cancelling my contract with MTN. Now I have to wait at least 6 months for another pre-qualification request. MTN needs to rectify my credit record with the IMMEDIATELY.