Hi there, Jamie! Thanks for getting in touch and sorry you’re hitting some trouble here.
It looks like this is a Javascript thing where, perhaps, the Javascript that is being loaded for the calendar functionality is conflicting with other Javascript that is being loaded by the theme or possibly another plugin.
For example, I see this in the console when I click the Previous/Next links:
Uncaught TypeError: undefined is not a function tribe-events-ajax-list.min.js?ver=3.9.1:1
Here’s a thread where the same issue was resolved by removing the conflicting version of jQuery from that page: https://theeventscalendar.com/support/forums/topic/ajax-error-with-events-list-next-and-previous-links/
I see that there are several blocks of custom jQuery in the header of your site. That’s likely where the error is where I would suggest starting.
Cheers!
Geoff