The way to block calls from unwanted callers from your smartphone depends on its operation system: generally, you use the same method for blocking certain numbers on all models of phone with the same operating system.

Or, you can download an app to help you block calls from unwanted numbers.

Here's how.

iOS

You can stop an unwanted person from calling, texting or FaceTiming you on your iOS device by:

1. Selecting them from your Contacts list: Contacts -> Settings -> Blocked -> Add New. Your Contacts list will appear, select the person and then they will be on your Blocked list.

For unwanted FaceTime and Messages contacts, follow the steps above.

2. Selecting them from your Recents list: Go to your Phone app, go to Recents, scroll to find the name or number, tap the blue 'i' on the right of the screen, scroll down the contact card that will appear, tap Block This Caller, and then confirm by selecting Block Contact.

Android

1. Go to the Phone app.

2. Tap the three dots on the top right of the screen (the More button).

3. Go to Settings, then Call, then Call rejection.

4. Go to Auto reject list.

5. Tap the + button, enter the phone number and hit Save.

Call-blocking apps

Mr Number: For iOS and Android. Block specific numbers or area codes. Users have generated lists of cold-caller numbers, and you can choose to block these, too, so you'll never be troubled by unsolicited sales calls again.

iBlacklist: For iOS only. Billed as 'the best call blocker app for iPhone', this app works totally silently to block calls and messages from unwanted contacts. You won't even know it's blocked a call or message, so you can stay blissfully unaware.

Safest Call Blocker: For Android only. Create a custom blacklist, block all numbers that are not in your contacts list, all calls from private numbers, and more. This app does notify you when it's blocked a call, but it makes sure that the blocked call does not appear in your call log.

(Note that while these apps may be free to download, you will need data to download and use the app. You can buy data bundles quickly and affordably by logging into My Vodacom »)