There are all sorts of reasons to block a number: an ex who won't stop calling, telemarketers who can't take a hint, scammers, or an aunt who wants to check in and see why you're still not married.
When your phone has buzzed one more time than you can take, you know it's time to block that number. But how? Here are the steps to take by popular operating systems and carriers.
To block your incoming calls so that anybody that calls your line, it will keep telling them "REJECTED"
Press *35*0000# and send.
Once this is activated, you will not be able to receive calls from anybody yet your phone is not turned/switched off.
To deactivate this code,
Press #35*0000# and send.