Charges on a paid up account

I am completely upset at how Edgars is tarnishing my credit records with the credit bureau. I have been recieving statements from Edgars indicating that I have paid up my account with a positive balance, just when I check my credit score I see Edgars has me in the red with a R400,00 balance that's outstanding. However, I have not recieved any communication from them or a statement to elaborate how I got to the R400 balance. Their call centre service is so pathetic one can never get through to get service and answers from them.