We also received Procedural Fairness letter. However, our situation is a bit different.
Even before the PFL, we received a request to provide additional documents to prove cohabitation (July 5th). In response, we sent a big package with 12 different documents (July 10th). This package was received at CPC-Mississauga on July 12th - we have a signature by the CPC staff downloaded from the Canada Post tracking site. To our huge surprise, on August 15th we received PFL that says, "we have not received any supporting documentation from you...." They are not saying "unsatisfactory evidence" - they are saying "no evidence received" which is a lie if you trust Canada Post's tracking system.
I am really at loss and don't know what to do. Has anyone been in in the same situation?