Page Builder Stopped working – no suggestions are helping so far (Theme: Barberia)

I made a website using a 3rd party wordpress theme (https://themeforest.net/item/barberia-barber-hair-salon-responsive-template/11450277) about a year ago. It’s hosted by GoDaddy. I believe it was since the latest WordPress update, Page Builder stopped working. I can see it at the bottom of each page, but only text in the editing window. I try to add rows or widgets using the builder (that’s no longer sitting nicely at the top of each editor window, but hidden down at the bottom), but nothing happens when I hit the button to insert. When I try to add a new page to see if the builder works, it has a 3rd tab, but it says ‘undefined’ instead of Page Builder.

Figuring out this part of websites is not my forté. I usually have my web host set everything up and I just start using the theme.

Suggestions I’ve tried that did not work:
– deactivating plugins, one at a time
– deactivating plugins, all at once, clearing cache
– temporarily using a different theme
– installed latest java
– updated PHP to latest version 5.6 (as the theme requested)
– cleared cache again
– tried contacting third party theme designer a month ago with absolutely no response.
… ahh!! What do I do?

Thank you!
j