this plugin broke my site in multiple ways

My page was working fine and well, but ti was a bit slow so i installed this plugin. Now the sort function will not work on the shop page anymore, the filter by price function looks wrong, and a widget in my sidebar will not display at all!

Ive disabled the plugin but the issue still remains, im so upset ive spent months launching this new site and now its ruined! please help!

The page I need help with: [log in to see the link]