Hello,
1) Make sure that you set up your form in right way https://contactform7.com/docs/
2) Check if you have this issue with our theme only or with default WP theme too.
3) I checked your site and see the error in console http://prntscr.com/hgtfvy
Read this topic and fix this error https://wordpress.org/support/topic/my-forms-is-not-submitting/
Regards