Edcon/Jet account system fails to update

For the 3rd month in a row they sending me e-mails and phoning non stop stating my account is in arrears..which is NOT the case yet again. I pay via EFT on the 29th of the each month and every month I send my proof of payments. I am beyond sick and tired of this... I am at point of closing my account without paying them the credit amount...that is how angry I am.