Here is the best way to avoid being scammed by a fake CRA caller.
Especially if they start raising their voice, threatening you, or tell you anyone is going to arrest you, seize stuff, or take your children.
Online, check for the return email address. It’s usually not a legitimate government email address which would normally end in “.gc.ca” or if it’s the CRA (they’re not supposed to / allowed to email you), would be cra.gc.ca or @cra-adrc.gc.ca.
If you’re not sure, don’t buy into the threats.