Apple India — "Privacy being compromised"

Address: 25/a31, Backside Marina Hotel, Middle Circle Road, Connaught Place, Delhi 110001

I have purchased a new Gadget (i phone 12 mini) through online site (flipkart), earlier it seems to be normal but i am being compromised with my privacy i.e. that phone consist of a face lock and i have locked it using my face id and retina but my brother was able to unlock it by his face.
I want to raise a complaint and regrading my privacy being compromised.