iPhone Block Caller
First, take the number you want to block and put it in your contacts naming it. If you need assistance with the steps to do this click here.
Second, there are then different ways to block this number. Go to Settings > Phone > Blocked > Add New
Find the contact number you want to block, choose it and that’s it. For alternate ways to block a number click here.
Android Block Caller
In your call log long-press the number until a popup appears and choose BLOCK NUMBER. That’s it. If you don’t get a pop window then you have a different android device (older versions of Android do not have automatic call blocking) so you have to go to the Call Blocking List. Depending on your device and what version of Android you will need to have the number in your contacts to choose it. Go to Settings > Phone > Call Blocking.The general idea is to click on ADD NUMBER and scroll to find the number you want to block and choose it which adds it to the list. Depending on your Android device these steps may be different. Android Authority gives step by step directions for various devices and carriers. HowtoGeek also has instructions.
How Does Call Blocking Work?
When someone you have blocked calls you, the phone will auto-block it. No ringing, no notification. Nothing. The caller will be sent usually after one ring (or no rings) to voice mail and you will see the name of the caller in your voice mail which you can ignore or delete. The caller doesn’t know you have blocked the number. MacWorld UK has an article, How to tell if someone has blocked your phone number on their iPhone, which will give some principles to suspect that a call is being blocked. You may want to read the article to know if someone has blocked your number!
How to Obtain a Number with No Caller ID
When a call comes in and the number doesn’t show this means the caller has set up No Caller ID. There are work arounds to obtain the number of a caller with No Caller ID. The Law Dictionary gives some legal ways to do this. c/net has an excellent article on how to do this. wikiHow gives three ways to do this. Trapcall offers a service to do this or if you Google it there are even more services offering to do this for you.