Solved Customize element: everything disappears

I have the same problem with footer an header.

I choose a style, then I click the link in "After choosing, you can then customize it here."

Ik click the edit button to change text in an element, and while typing, another window opens automatically and all items are gone with a message 'Message updated'.
When I try to save the original window, I get an error message that saving is not possible.

When I go back to visit the page, the entire header or footer disappeared. Cannot get this back.
If I select again this header or footer it is empty.

Just bought the entire package. I am very disappointed. And I would rather get my money back.

 

After opening the custom header style in Divi Library, straight away click to edit it in frontend / Visual Builder. > doesn't work, I get an empty page.

But I can turn of the wordfence plugin, do the edits and then turn it back on.

But how do I get back the footer an header that are now empty?

 

Didn't get the revisions possibility, so I deleted the header and footer that didn't work anymore. Imported the .json file again, but they're not back yet.

 

Ok, I took the json file of the child theme. Solved now. Thanks.