Vantage Theme-Home Page Not Working Properly on Mobile Device

I am new to WordPress and have run into an issue.

I am using the Vantage Theme hoping to take advantage of the responsive layout so that my web site, https://www.campheritage.org, will look good on all devices. When I attempt to access the web site in Safari and Chrome on my iPhone, I run into some issues. (I have disabled all plugins, except SiteOrigin ones. I am running the latest version of everything. I haven’t done any crazy coding or anything like that.)

1. My browser (Safari and Chrome) takes me to a “mobile version” of our web site. There is a black bar at the top of the page with the words “Menu” and “Blank Title” in it. My header and menu do not show up. At the bottom of the page, I am given the option to choose the version I wish to view, mobile or web. If I click on the web version, everything works properly.

Where is this unnecessary, unwanted mobile version coming from? Is this a browser issue? How do I remedy this for myself and my mobile visitors?

2. The content showing up on this “mobile version” of my web site is old. The content was replaced over a week ago. A photo link/button does not show up; however, a placeholder for it shows up and the link works properly.

Why is old content showing up on the home page of this “mobile version”? How do I get at least the current home page content to show up on this page?

Thanks for your help!