Tired

My Mtn account was handed over to this company and they reached out to me and i arranged payment with them i paid my monthly instalments and i paid every cent i then requested for my paid up letter and didn't get it months went by, I requested the letter and some said I should ask MTN and some said they will escalate the problem, I still requested my letter and they went silent until a rude agent called me this year saying i owe and if i don't pay it will mess up my credit and she hanged up . I am sick and tired of this back and fourth i need my credit cleared can barely take anything because this now shows as missed payment!! Ssda Fix this. Am tired now