Q: block this caller is not working

That is how it is suppose to work.

If you want the call never to reach you at all, call your carrier and request it.

That's as good as it gets. NO phone, whether it's an iPhone, Android Phone, Windows Phone, or old fashioned dumb phone can actually "block" calls. True call blocking must be done by the carrier. You're free to ignore the voice messages from people you don't want to talk to. If that's not good enough, contact your carrier and see if they offer call blocking and how much it costs.

Well, the only way to do what you want is to put them on the Block list. If you do that, you won't get any Voicemails. Sounds like you're trying to do this using DND, & that won't do what you want.

Actually, the blocked numbers on my phone simple get the standard telephone disconnect tone and are hung up on.  No voice mail, just disconnected once the called ID is matched to the blacklist in iOS.

Apple's own note indicatse they should not get your voice mail box either (http://support.apple.com/kb/HT5845):

"Note: Voice and text messages from a blocked contact will not be accessible."

I know because I blocked my office number and called my cell phone, and I was simply disconnected with no chance to leave a message.  According to Wired.com and CNET that is how it has also worked in their testing.

tickertock - be absolutely sure that the information in the blocked caller list is identical to the caller ID of those callers.  iOS uses blacklisting - it captures the caller ID and matches it to the contact information in the blocked caller list, but the match must be exact for it to work.

You could also try a basic reset of your phone as well (hold both the power button and the home button at the same time until the Apple logo appears).

<edit> P.S. as wjosten mentions - Do Not Disturb and Caller/Message Blocking are two distinct features in iOS 7.  Make sure you are not confusing the two.

As provided:

Well, the only way to do what you want is to put them on the Block list. If you do that, you won't get any Voicemails. Sounds like you're trying to do this using DND, & that won't do what you want.

It would seem this feature is spotty to actually giving the caller a "busy" signal.

I blocked my home number on my iPhone. Used the home phone and called. First try and second was right to a busy signal. Changed the phone number from (555) 555-1234 to 1 (555) 555-1234 in the contact list. Tried it again and it rings once and then to VM. Tried it a couple more times and the same, rings once and to VM. So I switched it back to (555) 555-1234 and it wouldn't go to busy signal.

I can see that the iPhone reacts to the caller. Because I left it unlock once during my testing. You know how the screen darkens just before it shuts off? Well I made the call at just the right moment, screen goes darker as the 1st ring on the home phone is heard. Then all of sudden the iPhone brightness up, and the home phone goes to VM. And the display time out is reset to my 1 minute.

KOT

tickertock wrote:

 

Perhaps a reset is what I will need to do, but I don't think doing that is worth it as I don't want to lose data.

You won't lose data.