Inconsistent, *********** and they don't care about customers

I bought a fridge and a laptop from them last year and made payments towards the account. In June I called 2 times to request a settlement letter. They gave me different amounts, I sent through an email and received no response. Settled the account on 29 June based on the settlement that was given to me by them and received a paid up letter, 2 months later I'm told the account still has an outstanding balance and the account is 2 months in arrears.