Block a User from Contacting You in iOS7

iOS7 allows you to block unwanted callers whose numbers are not stored in your contact list.
NOTE: - If you reset your iPhone device, you must block the numbers again.

In iOS7, the below steps must be followed to block a user from contacting you:

    ■Press long the Power button to switch on your iPhone device.
    ■Swipe your finger from right to left to unlock the phone and open the app list.

    ■Tap the Phone icon from the home interface.

    On the opened interface, make sure that the All tab is selected from the top.
    ■Tap the ‘i’ button with a cicle present in front of the number that you want to block.

    ■On the Recents interface, locate and tap Block this Caller from the available options.

    ■Tap the Block Contact option to block the caller.

    ■Once done, exit back to the home screen by pressing the Home button,and check if the modifications have been successfully made.