Nice to have you joined this thread, @wd6. 

I can see that you’re unable to reach out to our live Support Team. Don’t worry, I’ll share their operating hours and an update of the reported issue.

The Investigation No. 71760 has been resolved. However, another issue has been opened about undeliverable invoices. This is related to the previous investigation mentioned.

Please know that if you’re using Plus, Essentials, and Simple Start, our support hours starts by 6:00 AM until 6:00 PM on weekdays, and 6:00 AM till 3:00 PM PT on Saturdays. For Advanced, we’re available any time, any day. You’ll want to contact them again according to the operating hours of your subscription.

For more ways on how you can reach out to us, refer to this article: QuickBooks Online Support.

Feel free to read about the possible reason why your customers are unable to receive your invoices, and learn how you can fix them: Troubleshoot if customers aren't receiving emails from QuickBooks Online.

Drop a post anytime if you still have questions or concerns with invoices or any other sales forms. I'm always here for you. Stay safe.