> I forget which phone OS brand it was for, which is a shame as I might like to try avoid buying anything from them

That it is plausible to have come from any of the major ones just means that they all should be avoided. Which is of course not a very practical insight.

> unless it seems they have a fake them taking calls, no doubt that'll be a thing sooner rather than later

That would be the point where our friendship is over (or rather I acknowledge the fact that it was already over) and I delete & block the contact.