Can you clear your browser cache then try access your website again and see is it work fine now?
By the way, I've applied some of the fix into your site.
JoomlaFolder/plugins/system/metaman/metaman.php
JoomlaFolder/templates/ja_techzone/fonts/font-awesome/css/font-awesome.min.css
#mm .btn-toggle-mm.btn--tw {
z-index: 100 !important;
}
#mm .btn-toggle-mm.btn--fb {
z-index: 100 !important;
}
#mm .btn-toggle-mm.btn--base {
z-index: 100 !important;
}