Why is the Envy Theme mobile menu not working properly?

The Envy Theme mobile hamburger menu is not working. When it is clicked on the whole screen goes very dark and the menu appears at the very bottom after scrolling down? Our site is coloredits.com. Seems to work fine on the desktop - just the mobile is causing issues. Any suggestions on how to fix it?

Hi,

There is a JavaScript error. You should contact your theme developer to check it.

I did contact the theme developer. They want me to do a clean install! That is going to cause major grief as we run a customized app for our production system.