BLACKLISTED FOR WHAT I PAID FOR…NOT GETTING A PAID UP LETTER

MTN BLACKLISTED ME FOR THE CONTRACT THAT I HAVE SETTLED TGE AMOUNTS AND WHEN I CHECK MY CLEAR SCORE IT SHOWS THAT THE ACCOUNT HAS BEEN CLOSED.. BUT WHEN I TRY TO APPLY FOR A CAR FINACE THE TELLING ME THAT MY MTN ACCOUNT IS IN ARREAS HOW I DON’T KNOW… NOW THEY CANT EVEN ASSIST WITH A PAID UP LETTER