Bandwidth usage to high????

Hello,
I just received and email stating my bandwidth is high and that I will be shut down in 2 days with the current usage. I don't understand this and what is causing it. How can I fix it?
Thanks,
CV

Someone could be hotlinking a file on your site and when many people access/download the file, your bandwidth usage shoots up. One way would be to find out (logs) what file that is and either rename or remove the file.