Hacker News Reader

What? That is absolutely insane and I don't see how this could be regarded as anything but malicious behavior.

That's a badly thought out feature, it should be blocked unless you own the number wish to add it yourself.

I'm sure they consider that a feature, not a bug.

That’s not how it works. Or maybe you encountered a bug. Unlisting is permanent unless you install the app and activate your number to be listed again.