I usually define a IF state and use wp_clear_scheduled_hook
function. See example:
if (get_option('atenasupervisor_scheduler') <> 'Stop') {
echo 'Active ('. get_option('atenasupervisor_scheduler').')</strong></div>';
} else {
wp_clear_scheduled_hook( 'atenasupervisor_my_email' );
echo 'Not active ('. get_option('atenasupervisor_scheduler').')</strong></div>';
}
``