Restaurant Menu Plugin/ Dev not responding

Hello, I got a Restaurant Menu Plugin from Envato elements, but a few things don’t work properly. 1. I would like to add a 3rd column to the existing 2 columns but when I change the shortcode like suggested in the instructions nothing happens. My 2nd Problem is, that on mobile the menu goes beyond the first page. To comprehend what I mean just visit Hopefully you can help me I redownloaded the plugin and replaced it with the installed 1 cause I thought maybe the file was damaged or something but the problem still stands.
I very much would appreciate it if anyone would be able to help me or just send me in the right direction.