Please read this postIRCC agent told me they do not have my application even I have Delivery certificate from Canada Post. Canada Post and IRCC initiated the investigation but that does not mean the application would be found. The agent mentioned they have given AOR to all applicant received on 13 Oct and asked me I have option to send my application again.
https://www.canadavisa.com/canada-immigration-discussion-board/threads/lpcs-guide-to-october-2017-applicants-for-staying-sane.531269/