> I change mobile numbers at least once a year and most years I end up receiving calls/messages on behalf of the previous owner.
I had something very similar happen when I got a new number. I kept getting calls for the previous owner from what I assume to have been a bank, a library (for passed-due books no less; left a voice mail), and random people trying to contact this person. Not long thereafter, I started getting text updates from Facebook any time one of their contacts posted something. Facebook fortunately disables this with the text message STOP (IIRC) [1], but it bothered me that a nefarious actor could have passively collected the names of this person's contacts, messages, or more.
Not quite sure what to do, I did end up calling most of them back to inform them they had the wrong number, if they left a voice mail. The calls stopped about a year and a half later, and while I was somewhat annoyed at the time, in retrospect it could have been much worse!
I had something very similar happen when I got a new number. I kept getting calls for the previous owner from what I assume to have been a bank, a library (for passed-due books no less; left a voice mail), and random people trying to contact this person. Not long thereafter, I started getting text updates from Facebook any time one of their contacts posted something. Facebook fortunately disables this with the text message STOP (IIRC) [1], but it bothered me that a nefarious actor could have passively collected the names of this person's contacts, messages, or more.
Not quite sure what to do, I did end up calling most of them back to inform them they had the wrong number, if they left a voice mail. The calls stopped about a year and a half later, and while I was somewhat annoyed at the time, in retrospect it could have been much worse!
[1] https://www.facebook.com/help/225089214296643