Internet Explorer 8 issues

So I am having issues with the responsive menu in internet explorer 8. Due to the fact that it is not compatible with ie8, I wanted to have it completely removed it when ever the ie8 browser is being used. But I’m not able to remove it at all for ie8 and it’s taking up the entire width of the screen and totally bugged out and looks like a mess. I have modernizr installed and working, and I tried to play with the CSS and put the class for #responsive-menu to display: none, but nothing happens. I also tried to give it zero width so that it won’t show across the screen but nothing happens still. I’d appreciate if you could help me out, because I’m desperate! My website is i-stand.ca, you can check it out. Thanks!

https://www.ads-software.com/plugins/responsive-menu/