Cell-site simulators (CSS)—also known as IMSI Catchers and Stingrays—are a tool that law enforcement and governments use to track the location of phones, intercept or disrupt communications, spy on foreign governments, or even install malware. Cell-site simulators are also used by criminals to send...
Never going to be enough, use a VPN, and only use end to end encryption for calls…
Or use a VOIP service like google voice for the calls, at least force your monitors to get a warrant to google, make them do some leg work