Content being deleted after update

I have been working on our website change some text and content and sometimes when I hit the update button all of the work I have done disappears. Not only does the content disappear but occasionally some of the templates we use disappear. When we are doing the editing we aren’t editing the coding, just changing text and photos. To make matters worse trying to revert to previous revisions doesn’t work. I can see the changes and edits between the two revisions but when I try to restore them it doesn’t work. Would love some help with this issue.

The page I need help with: [log in to see the link]