Menus and Filters aren't working in Mobile or Firefox

The sidebar menus and filters in my store are not working consistently. They work fine in the theme editor, but live they do not work at all on a mobile device, nor on a desktop in Firefox, and in Chome they work sometimes but it’s not consistent from one page to the next. I’ve tried switching from the sidebar menu to filters, and the result is the same. They appear, but once you click they do not respond most of the time. I’m using the paid Effortless theme from the Shopify store, but unfortunately the theme developer has gone AWOL and their site is no longer accessible. Shopify is trying to get in touch with them, but in the meantime I have a store ready to launch but the navigation just doesn’t want to work.

I’m also using a hamburger menu but it is working flawlessly, quick and responsive on all devices. I’m only having issues with the sidebar menu and filters in the screenshots below.

Any suggestions? I’d appreciate any help anyone can offer here.

beunitedgear.com

Sidebar menu that isn’t working consistently:

Filter that isn’t working at all: