This feature may already be enabled on your device, but just in case, here's what you can do to turn it on: Open the Messages app. Tap the three-dot menu and go to Settings. Select Spam protection. Here's how spam callers get hold of your phone number. 1. They Bought It From Your Carrier. This doesn't happen much anymore but back in 2018, a few major US carriers - AT&T, Verizon, Sprint and T-Mobile - were caught selling location data to third parties. And if that wasn't enough, prior to 2016, they were also selling your phone.