Please spend some time to get to know your rights
Canada’s
Privacy Commissioner isn’t too fond of using SINs on mortgage applications. Her office put out a report June 8 that states:
A “SIN is not required to conduct a credit check.”
“There is no legislative requirement for the SIN to be collected for [mortgage purposes].”
“The Office of the Privacy Commissioner is of the view that the SIN should not be used as a general identifier and organizations should restrict the collection, use and disclosure of the SIN to legislated purposes only.”
“We recommend that no private sector organization request the social insurance number from a customer, and that no customer give the social insurance number to a private-sector organization, unless the organization is required by law to request it.”
If you're told otherwise, then they played on your ignorance!
https://www.canada.ca/en/employment-social-development/programs/sin/protect.html