I don’t have a land line. What a waste of money. Only when Superstorm Sandy took out cell and cable service did I need it – but we just got in the car and drive 5 miles up the road until we got a signal. I put all our cell numbers on the Do Not Call registry. The problem is that for a while, Apps would access your Contacts list and then sold the data. This was discovered a little over a year ago, and apps now need to ask your permission to access your contacts – and I nearly always decline.
On my iPhone, I do not answer any unrecognized number. If you click the lock button once, it silences ring/vibrate, but the call still goes through its regular process of 4 rings, then to voicemail, which some of the robocalls are programmed for. If you click the lock button twice, or tap the Decline button, it goes straight to voicemail, and the savvy caller knows that you are on the other end.
If no voicemail message is left, I search the phone number on the web, or use the Number Guru App, which people contribute their knowledge of certain numbers. If I confirm that the number is a spammer, I assign it to the SPAM identity in my contacts list. This way, if they call again, there will be no vibration and I have a separate ringtone (although the ringer is usually off). I also put spam texts in there – although I haven’t gotten any of those in a while – and again, any texts from numbers on that list do not make any sound or vibration.