[Exim] filter reject message

I believe this was addressed already but I searched for a while and
could not find the message.... how do I turn off the error email to
the postmaster generated by the system filter? also we placed the
message_body_visible at 500, and to my understanding this was supposed
to limit the returned message body to 500 characters? am I wrong? this
does not appear to be working as planned.

Thanks!
-jm