You can use fep_messagebox filter to add anything bellow message box.
add following code in your theme’s (child theme’s if you are using) functions.php

add_filter( 'fep_messagebox', function( $box ) {
	$box = $box . do_shortcode('[xyz-ips snippet="privacytel"]');
	return $box;
});

You asked to show un footer of “MessageBox”, that’s why i write that code for you.
To show under all pages of message system you can use fep_footer_note action hook.