Her mom says,"Ok, let's call your house and see if she was just at the store."
So she picks up the phone and calls 5-5-5-9-1-2-0. She hears an odd voice that says, "Hello. Who are you? I will hurt you. Mauhahahahahaha!" She slowly puts down the phone.

You decide to call the police.

or

You decide to call your mom and see if she answers the phone.