Fix your mistake

I gave notice to have my adsl cancelled and June was the notice period. I now get a statement that I am charged up until July 10 which doesnt make sense since I didnt even have ANY service on that day. I want the correct statement to be genarated so that I can pay it off please. What I know is that I am not going to settle this last invoice until it is fixed. I just wanted to be clear on that one.