I checked again, Interested to sponsor form starts with IDB.... . Than I checked my mom supervisa stamped on her passport. Thats different . Than I checked another document which proves my relationship with my mother, That starts with AB--- but numbers still dont match..the # starting AB is probably your interest to sponsor confirmation #. check your email in 2020 to verify.
the status document they mentioned in the email, is it your mother's or yours? since we didn't submit any ID for our parents in the interest to sponsor form, this request most probably was raised because your situation changed (sponsor), rather than your mother's (applicants, unless you submitted the wrong spelling of her name). Sponsor's name change, status change (PR to citizen), address/contact change can cause this request. it's best if you have kept a copy of what you submitted in 2020 to verify.
So I am bit confused .
only thing that changed from the the moment I submitted my interest to sponsor to time of applying is my mother 's address as I mentioned Canadian address as she is/was in Canada at the time of sending application . Rest, my address, job ,status , income everything is same.