@ sick man
Sorry to say, but i think you are unnecessarily panicking.
-- you had sent the package on May 1 by Aus Post.. for which you don't know when it got delivered to CIO. Its universal truth that Departmental Posts take much longer to deliver internationally.... upto a few weeks.
Assume, if you have Couriered it from Aus on May 1, it would take atleast 4-5 days to reach NS... and CIO is just processing May 5 Applicants as of now. ..
so there''s still time for your Application to be picked up going by that assumption.
-- Regarding your add.. you filled the correct add (PO Box) which is as per the Guidelines for sending thru Regular Mail- put PO Box add.... so what makes you feel that it might be lost ?
-- Moreover, you have sent the Appln quite early (except for delays in Post).. you should be well within the Cap even for Hottest NOC in Canada !
If all goes well.. you will receive PER sooner or later, suggest you to hold on to your horses

Just wait for sometime for Aus Post to revert to you on your delivery status.
Good luck !