Customize Section, Zerif Pro

I am having lots of issues with my customize tab for my website.

First problem: In the big title section when I was making changes to the section (changing the photo, text and color) it refused to save. I would click ‘save & publish’ it would look like it would work but when I would try to navigate away the site asked if I was sure because I would lose my changes. The changes would never save. I tried shutting my computer off and on, closing out the browser completely and tired it on 2 of our work computers and my ipad (which was on our office wi-fi). The problem wouldn’t fix…

So I went to the theme’s page to see if I needed an update (just in case that was the problem). I clicked the update. I don’t know to which number version. AND NOW….

Second Problem: Whenever I try to click the customize I get the following message:
Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

I tired shutting down my browser, clearing cookies and cashed data and I turned it off and on and tired it on several different computers. No results.

I NEED HELP!!!