**** billing when account was closed 2021

Mtn is a **** indeed . I opened a contract with them 2019. I called to settle the my account in November 2021. How as I want to buy a house it's appearing on my credit score that I owe them R806 ...how is that possible when I settle my accounted paid R5980 to settle it it was closed . When I call they taking me pile to post telling me I must call legal I call legal they saying retention ,they retention confirms it's closed therefore why am I billed on a closed account. Am asking for recording as they claim we been recording they claim retention in cape town were not open ...Imagine nobody wants to account. Asked for the person whol processed and said I must pay R5980 they hanged up in my ear ...****mers indeed Mtn never open contracts with them a 2021 closed case it surfaces now what the hell!!! Credit score ruined cause of them !! Am furious