https://www.consumer.ftc.gov/articles/0108-na ... try#registering
Q: How long does my phone number stay registered?
A: Telephone numbers on the Registry don’t expire. We only remove your number when it’s disconnected and reassigned, unless you ask us to remove it.
Hangs up when call is answered. I called number back and get recorded message saying to "press one" to add one's number to do not call list. Not able to get a real person. Have received two calls to date. Whoever called must be getting phone numbers off Craigslist, that is the only place I use the phone number they called me on.