How my iphone unlocks with my sister’s face ?

Dear Apple customer service provider,

My iphone unlocks with my sister’s face although we aren’t twins nor very similar to each others

this is terrible while this is my first time to have an iphone in whole life !

i should have my own security as an individual

and this is cannot be achieved with these failures!

i am working at PALTEL ISP as NOC engineer and you know that security is a big matter in such kind of work

please i need an explanation because this breaks the confidence between the customers and Apple company as it’s known well for its high security standards!

waiting to hear from you as soon as possible,

Regards,

Reham Khabbas