如果係三唔識七嗰d,威脅會傷害你既家人,已經屬 criminal intimidation,絕對可以報警。如果唔想搞大,都可以 report for nuisance (though the fine is minimal). If proceeded, the court can issue injunction order. Remember to screen cap all the details and print the copies out, then produce to police when making a report.