Fantastic - thank you! No the friend for whom I'm asking has no voicemail, so this does the trick. Thanks again!Go to Settings>Sound & Vibration>Do Not Disturb, and turn it on. Then in the People section, for both Messages and Calls, toggle on the checkbox for Contacts. Other people who call would go directly to voicemail. Or are you trying to completely block anyone who isn't in your Google Contacts (i.e., not even let them leave a voicemail)?