Writ of Madndamus works only in case your case has been delayed by over an year. So 1.5 years from the AOR date and it cannot be done collectively and has to be done at individual level. Legal fees are involved and depends on lawyers ( 3k+ $) and IRCC may or may not expedite even after that. Many Security Screening candidates consider that option and it has worked out for some.https://www.canadavisa.com/long-delays-canadian-immigration-application.html
One of the options given is:
Is this really an option?
- File suit (Writ of Mandamus) in the Federal Court of Canada. Our suit will ask for an order that would require the Canadian Immigration Visa Office to bring your application to final disposition in a timely manner.
I am not saying we should go to an all-out war with CIC. But an application that is held-off 2 months after Approval, deserves some reasoning.