How do people set up 24x7x365 support for SaaS products?

Intercom integrated with Slack can track the issues and the time spent, and they offer
pretty comprehensive reporting and automatically ask for customer feedback when tickets are closed. Another one that you can use is chatlio.com - which ties directly to Slack. You can also setup a configured help desk number. 24x7 SLAs only for PO/Urgent issues and the rest of the issues are only answered during business hours. And if you really want enterprise-worthy support, you need to invest in enough people to really cover your Pager Duty queue around the clock.