A useful link is to look at the operational guidelines and operating manual:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals.html
Relevant to this case:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/permanent-residence/non-economic-classes/family-class-decisions.html
If you scroll down you can find the section on refusal. I'm still taking a look.
But (for example) in the section on refusals there is the following section:
"Reconsideration and enquiries after refusal
Applicants or their representatives often submit information after a refusal and request that an officer reconsider the decision. If an office receives a request to reconsider a decision, an officer must consider the request and decide whether or not to exercise their discretion to reconsider the previous decision."
Read carefully, as there is language in there that states such reconsideration is more of an exception. But the officer
must consider the request.
But it gives
@passenger19 the opportunity to (in parallel to appeal) request the file be looked at again and provide additional information; it's possible also (for example) that MPs office inquiry will mean someone more senior looks at it, and not all reviewing officers will see the same thing. (And like any system, sometimes the squeaky wheel does get the grease). It also makes sense to attempt to provide some additional information, whatever can be found, to respond to the reasons of the determination that you weren't common law. (Even if you think you provided everything, additional information has to be considered)
Another key quote from this same section:
"A (non-exhaustive) list of factors that may be relevant to consider:
- whether the decision-maker failed to comply with the principles of procedural fairness when the decision was made
- if new evidence is submitted by an applicant, is the evidence based on new facts (i.e. facts that arose after the original decision was made and communicated to the applicant) and is it material and reliable. Decide whether that evidence would be more appropriately considered in the context of a new application"
I bolded the part above that it would seem to violate the principle of procedural fairness to not provide a procedural fairness letter (i.e. an opportunity to respond if the reviewing officer did not feel the information provided met the level needed).
Note: I would not get overly 'legalistic' in this, in that I'm not 100% certain that the procedural fairness letter is required by the operations guide, but refer to the principle of procedural fairness, that they certainly could have given the applicant a chance to respond and instead jumped directly to refusal. (Although covid not a direct justification, given delays in processing new applications, appeals, and others, it is particularly unfair and arguably uncompassionate to go direct to refusal in cases where judgment of the reviewing officer was the deciding factor, and not some obvious non-admissibility criteria like actually living together for less than the required 12 months.
I really suggest
@passenger19 that you and spouse look at this guide to get insight, for example I'm sure there's a section on evaluating common law and you can buttress your arguments by 'borrowing' language from the guide wherever possible. (I'm going to look myself but I'm not an expert)