>>10 People will say litter ally a n y t h i n g just to get in your head and rustle your jimmies, so don't fall for it this bullshit. When someone messages you something like that don't get all flustered because odds are they're full of shit. Just ignore 'em, or be dismissive if you feel that you have to say anything at all. Which you really shouldn't in the first place because it's a really shallow attempt, like fuck. My dog has shat out more intimidating shit.
Now, if you do feel that your life is in danger, take a screen-cap of the conversation and remember that if the sorry sucker does come to your door-step, you're free to beat the living fuck out of em' in defense of your family, yourself an your property, promptly call the police after beating said bitches to a pulp, forward the screen shots of those messages to the persecuting law-enforcement and there will be a couple of now prison bitches getting anally probed by some actual hard-asses in the prison penitentiary for the next life-time or so.