It is Vivint Smart Home Security
You are either an emergency contact listed by someone that uses their service, or you use their service and are late paying your bill. They have never called me other than to remind me a bill was due after my father passed away and it was his residence that the system was protecting. A simple courtesy call letting me know I overlooked paying them. He had his bill payment set up through his bank account, now that he has passed away, I have taken over paying the bill and have missed paying it a couple times. They will cancel his contract with a death certificate, however we have kept it active since the home is not occupied.
It's a legit alarm company. They just called me in regard to my neighbor's alarm. Never knew I was on their call list but now I know I am! But they left a message with a call back and my neighbor confirmed the company.
Vivint is not an excellent alarm company. I canceled my service, removed all of their equipment & they called me 6 weeks later and left a message to tell me my alarm was going off. I called city police department to see if a patrol car was dispatched to my residence & was told no. Thankful for that or would have been charged a false alarm fee. I wouldnt recommend this company to anyone. I think they take your money, call you from time to time to report your alram is going off just so you think they are monitoring when they are not.