Hey Erin,
Thanks for reaching out to us!
Looking at your site, there appears to be a javascript error on the page which is most likely the primary culprit for why the mobile calendar isn’t working as expected on mobile. Have you tried disabling the other plugins and switching to a default theme to see if that resolves the issue? If so, you can then reactivate the plugins one by one and reactivate your current theme to see where it breaks. This will give more information as to where the conflict lies.
Let me know if this helps.
Thanks!