Lack of respnse

Surely when one receives a statement everything should be included on the statement that you are required to pay at the end of the month, and not find out when you go to pay according to the sent statement that there is an extra amount to be paid. If that amount is not on the statement sent then it must be put on the next statement. Also why does Edcon customer relation take almost five weeks to reply to a query and then they conveniently do not answer all the questions asked of them, I am still waiting for the answers to 3 questions asked