Sometimes you might get a call from a person you'd prefer not to hear from, like a telemarketer or someone who's bothering you at odd hours of the day. Fortunately, iOS 8 can block calls as well as iMessages from annoying contacts and non-contacts. Read on and we'll show you how it works...
Block inside of the Phone app
To block a caller inside of the Phone app, take the following steps:
Open the Phone app on your iPhone
On any of the recent callers, tap the "i" button in the corner
Scroll to the bottom of the Info view and select "Block this caller"
From now on, when this person calls your iPhone, the call will not ring through. Note that this is caused by your iPhone rejecting the call; the call will still register on your cellular account. This method does the job in normal circumstances, but for more aggressive blocking, you may need to sign up with a call-blocking service through your cellular provider.
Block inside of the Messages app
Inside the Messages app, you can block a person who is repeatedly texting you or spamming your iMessage number. Here's how:
Open the Messages app on your iPhone, iPad, or iPod touch
Navigate to the iMessage thread that is spamming your device
Select the Details button in the top-right corner of the screen
Select the small "i" button beside the contact's information
Scroll to the bottom of the Info view and select "Block this Caller"
Note: If you've already blocked a caller using the above method, the caller will be blocked for both Messages (SMS and iMessage) and phone calls.
Remove a block
When you want to remove a block, simply open Settings > Phone > Blocked. Here you'll see a list of all the numbers you've blocked. You can remove the block for any of the callers on this list by tapping the Edit button, and then selecting the small Red "-" button beside of the caller.
When you remove a blocked contact, you'll be able to receive calls, SMS messages, and iMessages from them again immediately.