I've been getting calls off unknown numbers?

On my iPhone 4 I've recently been getting calls from a private number. Every time it rings, it says "Unknown Caller" and it's really annoying! How do I block these unknown calls? I've heard there's a way to stop you from getting "Unknown Calls" but I don't know how to do it and if anyone knows I'd be so thankful if you told me! I really need it to stop!

You can't, but you can block the certain number. Here's the link

Block calls with no ID

Read the manual it's what it is for!

  • Unknown iPhone passcode set by unknown person? A passcode has been set on my iPhone without me knowing, now it is locked up. It says here to connect it to my computer and back up then restore my iPhone. Will this clear everything off my phone or will it be the same as it was before it got locked? I have only attempted unlocking it about 5 times in fear of disabling it. I do not want to back up then restore it if it will clear everything off and transfer it to the computer. Are there any alternatives to unlocking my iPhone?
  • IPhone app that blocks unknown numbers calling? What apps blocks unknown numbers on iPhones? I don't care if you have to pay I just want one that works well. I'm NOT going to jailbreak my phone for this either.
  • Iphone 5c incoming calls just say UNKNOWN CALLER no phone number displayed? I'm hoping someone might have a suggestion. I recently switched to an iphone and when I receive incoming calls no number comes up it simple says Unknown name. I've never had this happen with a phone before. I contacted the carrier who have no answer why this is happening and are going to look into it. In the meantime I don't know who is calling my phone. I can't figure it out if anyone has a answer or knows what might be going on I'd love some feedback.
  • How to set a ringtone for unknown numbers on my iPhone? I have a 3GS and three ringtones for separate groups of contacts. What I need to know is how to set a ringtone for any number NOT in my contacts list? I'm getting so many junk calls its doing my head in. And yes I'm registered with TPS and O2 Spam Alerts, if anyone wanted to suggest that, but it's not stopping them!