Not that kind of letter but dump it in the rubbish anyway.
Having all three offspring now kitted out with phones has been rather life-changing.
I knew it would be, of course, but I couldn't have predicted quite the effect it would have.
It has opened them up to a whole, quite terrifying, world that many of us parents aren't privy to as we enjoy the peace of, say, the school holidays while they're often kept entertained and hunched over these small devices.
But only days after the twins' birthday, the high excitement of owning their first phones had begun to wear off and I noticed changes in my daughter's mood. Usually of sunny disposition, she was becoming irritable and even a little stressed at times.
After I pointed this out to her on several occasions, I think she had the good sense to realise it herself. She eventually put the phone down and came to tell me about a few things that were bothering her.
Most of their friends and classmates are on Instagram so I had reluctantly let the twins sign up. This followed a privacy lecture about only letting friends follow them: It wasn't a popularity contest to see how many followers they could get, and they were not to invite strangers into our lives via their social media. I finished with an anecdote about the creepy foreign man on the other side of the world who hacked his way into an Auckland couple's home recently via their baby monitor.
But it turns out that even what their primary school classmates are posting is disturbing enough. I was shocked by some of the language coming from these 10-year-olds.
One girl had also posted a chain letter stating if it wasn't forwarded ''you will die!''
I explained to my oblivious 11-year-old that chain letters have been around since before her grandparents' time, except they used to arrive via the letterbox - and they are to be ignored.
I wondered if some of these parents have any idea what their children are getting up to. Not that I could blame them completely; many of us are guilty of taking advantage of our kids being entertained, oblivious to what is actually going on.
But I'm glad my daughter was disturbed - and still innocent enough to tell me - and I made her leave the Instagram conversation. But this was when her anxiety came in; she became worried her friends would judge her for leaving.
I told her to just blame it on me and I'd talk to her teacher about suggesting a no-names conversation with the class and perhaps even sending out a generic memo to parents. My daughter, of course, was horrified her mum was going to be such a nark, albeit in a non-name-dropping way.
Meanwhile, I'd joined a group chat of my own with my three kids. It's a great way of keeping in touch with them when they are not at my house. It's not so great when your newly inducted twins keep bombing your phone with silly voice messages and videos featuring equally silly GIFs and music.
But then on Sunday morning, while still in bed and after a series of these exasperating group-chat bombs from upstairs, I decided to use it to my advantage.
"Make me a cup of peppermint tea please someone!" I posted.
Several seconds later I heard the jug boiling. The real-life jug. They are not completely lost to cyberland yet.