Paid up account still no paid up letter

On 2nd December i was called by Boitumelo from Barrets & associates to settle my account which i did on December 4th and sent proof of my payments to payments at barrets till today i have not received my paid up letter everytime i call they consultants refer me to someone else. i then spoke to Pulane who promised to send my paid up letter before the end of December. this is affecting my credit record because it's still showing as if i owe them.