Good evening Robert and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the tickets no longer being editable for you. Yikes!
I would love to help you with this topic.
When something like this happens, after a backup of your database, we typically recommend downgrading back to the last working version of our plugins on your site.
I recommend reading the following: https://theeventscalendar.com/knowledgebase/downgrading-plugin-past-version/
Could you also please send me a copy of the latest version of your WordPress theme / child theme via a link to a .zip file link (stored Dropbox or Google Drive) so that I can run some tests on my end ? I recommend a private reply for that purpose.
Please ensure you are using the latest files as found on your actual website.
This way I will get access to any updates or customizations you might have made.
Hang in there!
Geoff B.