Hey Mahtax, I'm not sure how the situation is at the MIFI office in Montreal - they haven't been very communicative about changes in their work schedule during the pandemic. I would assume that if your CSQ application was sent after employees were sent home, then it is most likely sitting there in the MIFI mailroom. I'm just speculating, though.
We were lucky enough to send everything before all of this happened and got acknowledgment roughly 2 months after sending our application with express DHL (I can't remember exactly when they officially received it). You can see my timeline in the Google Sheets document...we still don't have our CSQ.
I don't think calling will do any good right now. If I were you, as difficult as this may sound, I would wait until this is all over and I'm sure it will come through eventually. The federal government shouldn't expect you to provide anything urgently at the moment, so just be patient.
I've seen a lot of people writing about providing a receipt that their CSQ application was received. Where is everyone reading about this? As far as I know, we simply need to wait for the CSQ to be granted before the rest of the application on the federal side can be processed. Québec will directly inform your visa office about their decision (which is almost inevitably yes, unless your documents aren't in order). Where is everyone getting this information?