Highend menu broken on iPhone

WP Live tech support has been working on this since last Friday and no one has figured out why the menu won’t show on my iPhone. For a while, the hamburger menu was showing but not working and now it is not showing at all.
We added a plugin called main mobile as a workaround and that hasn’t helped either.

Is this a problem with my personal setup or is it a theme issue on your end?

my website is rvexplorersguide.com

Thanks in advance for your help.

Kindest regards,

David Isham