Good evening Steve and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the calendar disappearing on you again. Yikes!
I would love to help you with this topic.
I have also noticed that none of the single events display as well.
When I click on a link, I get an error 404 message.
My first recommendation would be to go through the following steps first: https://theeventscalendar.com/knowledgebase/fixing-http-404-errors/
Secondly, it might be good to make sure that you flush your cache manually (or deactivate the caching plugin temporarily to see if that helps).
Let me know how that goes.
Best regards,
Geoff B.