Injustice to clients

I had an account with Hifi corp,paid it up in April 2020 to date my credit bureaus status hasn't changed. I am unable to buy a house due to ****en incompetence from this Group. This is unfair practice and injustice to consumers. They handed over my account to DMC whom gave me a balance to pay,and I paid it and they send me a paid up letter now few months down I get an email saying I have an outstanding balance..****en How..Fix your mess