I got this on the same day. And, I actually called the number. 866-316-6701.
Sounds like a telemarketer in the background. I let the guy who answered look at terminal, which showed this document:
_____________________________________________
Last login: Sat Jul 11 13:57:01 on ttys000
Remys-MacBook-Air:~ remy$ netstat
Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp4 0 0 192.168.2.58.59819 mcs23-1-isp2.ams.https ESTABLISHED
tcp4 0 0 192.168.2.58.59818 mcs3-2-isp1.ams..https ESTABLISHED
tcp4 0 0 192.168.2.58.59817 mcs23-1-isp1.ams.https ESTABLISHED
tcp4 0 234 192.168.2.58.59816 mcs23-1-isp1.ams.https ESTABLISHED
tcp4 0 0 192.168.2.58.59414 17.172.232.9.5223 ESTABLISHED
tcp4 0 0 192.168.2.58.59413 17.143.163.165.5223 ESTABLISHED
udp6 0 0 *.52451 *.*
udp4 0 0 *.52451 *.*
udp6 0 0 *.57937 *.*
udp4 0 0 *.57937 *.*
udp6 0 0 *.63192 *.*
udp4 0 0 *.63192 *.*
_____________________________________________
He proceed to tell me I have 6 "hackers" logged into my account and no security settings.
For $199 or $399, I can have this cleaned up. It will take about 3 hours. He tells me he's at an "Apple certified" company. Shows me the company's website at Diving Support:
https://www.divine-support.com/index.html
Like most, I was searching for images, when one of the images took control of my Safari browser. When I tried to back out from the alert, it actually changed to a PC blue screen freeze. Heh.
Never call a phone number on a "system alert."
Yeah, it's a scam. And they sounded busy.