Hey
I hope you are doing great!
Sorry for this problem i have updated the plugin with latest telephone JS, So please hold on till next update release in next few hours then update the plugin and test the booking
Also your hosting provides some type of cache which brings some problems, If you have option to disable the Cache in hosting side do that or get CDN and Caching disabled for Booking to work smoothly
We can also offer you website hosting you can let me know if you're interested anytime for only 96$/Year
Also once you receive update please test the booking form and let me know if any further issues WordPRess holds update for 6 hours to release so it's expected 6 hours from now