The junk calls, and spam emails we have been getting are all linked to this...<p>It has been going on for a long time. I was working on testing MFA on Microsoft Azure with a brand new phone number I registered, was not getting any junk calls at all before I started testing. The minute I submitted my phone number to the authentication app for Azure, I started getting random calls on my phone. The minute I submitted my email address for verification I started getting junk mail.<p>Many of these companies are using 3rd party libraries that snag your number and store it insecurely and/or even sell it to spammers. Companies should be held accountable for it, and customers should be able to opt out. Not everyone can simply change their phone number.<p>Google (Android) and Apple should also be required to provide better ways of blocking unwanted calls, like being able to use wild cards e.g. (301)299-* to block all numbers within a range.<p>I think the biggest problems preventing this issue from being resolved is that mobile carriers are profiting from the surging airtime fees, and that most people don't really know that this is all happening behind the scenes.