Dolomats0 on "[Plugin: Jetpack by WordPress.com] Change Label of Send message button in Contact Form"

Hello

I want change the Text in the Send message button (Send Message)
i tried this but didn't work :

[contact_form submit_button_text='Envoyer']

And i want change the Message that come when message sent.
i tried this but didn't work :

function amgenna_change_grunion_success_message( $msg ) {
global $contact_form_message;
return '<h3>' . 'My custom success message' . '</h3>' . wp_kses($contact_form_message, array('br' => array(), 'blockquote' => array()));;
}
add_filter( 'grunion_contact_form_success_message', 'amgenna_change_grunion_success_message' );

Thank you For the Help

https://wordpress.org/plugins/jetpack/