How can I stop all of this hacking????

To whom it may concern:
Our local government website has been getting hacked in over and over by those damn chinese honkers or hackers or whatever. They hack in and we fix the problems, then they do it again!!!!! Is there any documentation anywhere on how to stop this? They are leaving the message “F**k USA government and F**k Poizonbox.” I know the whole story I just need to know on how to stop it. Thank You very much.