call blocking.

[ashleylawless]

Where has the call blocking function gone. I got android 4.3.

[Johan]

There is no definitive block feature by default in the phone.

What you can do is to send a contact directly to voice mail.

Open the contact and select to edit it. Press the three option dots and choose to send all calls to voice mail.

If this is not what you're looking for I suggest that you check for call blocking app's on Google Play store.

[stormmaker]

better still, just contact your mobile carrier and ask them to block a number from contacting your device, which they can easily do.