Any changes made to site in WordPress admin are not updating on live

My client is having a significant problem updating anything on their WordPress site.

Here is a summary of the problem:

1. Logged into webpage as administrator.
2. Made changes to text in the massage section (or any other section), made changes to navigation
3. Hit update to save changes.
4. Hit preview page: it shows the updated change
5. log out and type in URL for webpage. Changes show up on that computer immediately.
6. Changes do not show up on any other computer (with the exception of one computer, see #8). Even tried clearing all caches, testing different browsers, and searching from cell phone browser. Changes only visible on the source computer.
7. After 1 hour, changes that were visible on the source computer have reverted back to original text within all browsers (firefox, IE, Chrome).
8. One computer in our office still shows the changes within IE, no changes seen in Firefox or Chrome.
8. This has been happening since 10/16.

I went in a looked myself and sure enough, the changes they had made in the admin are visible in the admin only, but are not visible on the live site.

Do you have any idea what’s going on?

The site has been up for a year with no previous problems. No new plugins have been added and it has been working perfectly with existing plugins until a couple of weeks ago.

The site is http://www.watkinsfamilychiropractic.com

Thank you!