Adding a filter hook for sending email or not

private function compose( $send = true ) {

        /*Adding a filter hook for sending email or not*/
        /*=========================================================*/
        $send = apply_filters( 'ctf7_send_via_mail' , true );
        /*=========================================================*/

		$template = $this->template;
		$use_html = (bool) $template['use_html'];
   /*
      ...
   */
}

Only recording messages in the back-end using Contact form 7 and Flamingo.

https://wordpress.org/plugins/contact-form-7/