I saw a great idea on Rotorburn - if you send an e-mail, mail in a copy as well.
It will make sure that Parramatta Council gets your submission, especially if you have made some serious effort to discuss the issues.

If you are one of the guys doing a petition, make sure that you keep a photocopy of it (original must go to Council), particularly if you mail it in.
If you've got access to a fax, you can also try faxing an extra copy to them but mark that as "COPY".