These guys look like pretty big time scammers.
Here's a couple of their websites:
[url]https://mackeeper.com/[/url]
[url]https://zoomsupport.com/[/url]
Some of their numbers:
18009348196
18008045671 - down at the moment - wonder why :)
18008268178
18007878041
18009618537
The scam seems to be based around this particular piece of crap-o-ware:
[url]https://www.pcrisk.com/removal-guides/15421-kromtech-net-ads-mac[/url]
They claim to be a 24 hour operation so if you're stuck at home looking for somebody to talk to, I'm sure they'd love to hear from you.