Account problems since July

Good day, I am trying to resolve an issue on my account since July 2017. I've requested to settle my account in July, I've received a settlement letter to the value of R86.16 knowing that my account will then be in a credit of R13.84. I am however receiving invoices from Game since then stating that I owe more monies on my account, I will then phone the call centre to recity and then balance will go back to R0 owed. I want this account to reflect the Credit of R13.84 plus interest from July.