Do you use the iOS apps for Google+, Gmail, Facebook Messenger or any other messaging service? Then you could be at risk from this tricky scam.
Apple has a special feature for apps that lets them make phone calls when you tap a link. Other than that tap, however, you don't need to confirm that you want to make a call.
Unfortunately, a programmer can make the link say anything they want. That means a scammer could email, message or post a link to social media claiming to be something you might want to see.
Once they trick you into tapping on the link, your phone will call a premium phone number the scammer has set up. When the number picks up, you'll be automatically billed for the call.
On the plus side, you will see the iOS dialer screen come up when this happens. If you're fast enough, you can end the call before the scammer's phone picks up, but if you aren't sure what is happening you might not make it in time.