Hi Greg!
I’m sorry you are experiencing issues. Let me help you troubleshoot them.
When you say ‘our event categories section has disappeared from our “Add your Events” section’, what do you mean by event categories section? Were you making a template customization for the Add your Events section, that you don’t currently see? Perhaps you can share with us a screenshot of the issue and a link to that page, so we can take a closer look.
Also, when coming back, could you please share with us your latest system info by following this guide > https://theeventscalendar.com/knowledgebase/sharing-sys-info/
Thanks,
Victor