"Who is this ?"

So I’ve had various conversations with this chap over the last six months.
FB, email, text, phone and in person
Got a random ‘how are things’ email last week. All good.
Last night I had a question so I pinged off a text.
Reply come back: ‘Sorry, who is this?’
So said person clearly hasn’t saved me to contacts and must have deleted prior text thread.

When is it safe to assume person you txt knows who you are and you don’t need to ‘sign-off’
I always save names to contacts if I’m likely to see/chat again.

Maybe they got a new phone and were too lazy to copy old contacts across ??

His partner got suspicious?

I don’t keep any contacts on my phone, I’ve memorised all the important numbers, I only communicate via secure channels, hit me up for my PGP key

^I’ve seen your pigeons flying about