Mobile menu not showing with Planyo jQuery integration

Hello,
I love the Athena theme, but I have a problem with the mobile menu on the page where I got Planyo booking system integrated. I used their plugin for integration and it seems to me that their jQuery is problematic with Athena theme. I really think its theme specific problem as I tried to simulate the same situation with some other themes, but on those occasions, mobile menu was showing. This is the page in question http://marinero-sailing.com/booking/ If you check it out on mobile device, you will see that there is no mobile menu (hamburger) showing. Other pages are working well, pages where Planyo plugin is not used (where there is no call for their jQuery file). This is the jQuery that is a problematic: https://www.planyo.com/Plugins/PlanyoFiles/jquery.min.js
I tried not using that jQuery, but then that Planyo integration doesn’t work well. Could you please help me out here? Thanks in advance