Right move, too late. Everyone I know has largely abandoned the possibility of answering unknown numbers.
I tend to answer even still.
I tend not to answer, because it is _always_ an unwelcome interruption.
Using an ancient vestigial telecommunications system as your lifeline is your problem.
Longtime friend called me from one of these places yesterday. I answered only out of common courtesy, fully expecting a robocall.
I think ideally people should use something like xmpp or email.