Ah, your government at work, spying on every detail of your personal life. However, for once the government got stopped.
U.S. government investigators have lost a case to force Facebook to wiretap calls made over its Messenger app. A joint federal and state law enforcement effort investigating the MS-13 gang had pushed a district court to hold the social networking giant in contempt of court for refusing to permit real-time listening in on voice calls. Details may be found in an article by Zack Whittaker in the TechCrunch web site at: https://tcrn.ch/2IoeJAE.
In the meantime, if you want to block government wiretapping of your voice calls and text messages, simply use an encrypted messaging and voice calling app, such as Signal.