Since October of 2012, spouses of Canadian citizens or permanent residents have had a condition to consider for their permanent resident status in Canada, if their marriage or marriage-like relationship is less than 2 years old at the time of submitting sponsorship or have a lack of biological child between them.
After two and half years, there are a number of cases Citizenship and Immigration Canada is investigating to remove those spouses with conditional permanent residency.
In many cases, CIC is investigating based on tips received from families or public. After their initial investigation, CIC would contact such spouses for proof of their two year cohabitation after their date of landing. In addition, about 10% of total applicable spouses are being contacted randomly for quality control as well, without any tips or concerns in the first place.
Contacted spouses are given a fair chance to be heard with an opportunity to provide documentary evidence to prove their two year cohabitation. If CIC decides to take away their conditional permanent resident status, then such spouses have a right to appeal to Immigration Appeal Division.
If you get contacted by CIC to seek your documentary proof for two year cohabitation, I recommend you to seek legal advice in advance before your case gets escalated to investigations and beyond.