Macworld How to block spam calls on your iPhone "We're calling about your car's extended warranty!" Spam calls have gotten way out of hand. It used to be that you could simply ignore anything with a caller ID of unknown caller or a distant or toll-free area code. Today, thanks to automated systems that spoof phone numbers, scammers and spammers can call you from numbers that look like they're from right in your neighborhood. Many people now get several spam calls every day, half of them about their car's extended warranty. Fortunately, your iPhone has a couple features that can help combat this nuisance, and they're really easy to use.