PAY PER VIEW PLUGIN - CUSTOM FIELDS PROTECTION

Hi,
I'm on a project for a client who wants to protect several fields of the plugin wp resume manager. So i followed this thread to integrate custom fields to the pay per view plugin:
https://premium.wpmudev.org/forums/topic/i-dont-know-how-to-integrate-the-plugin-pay-per-view?replies=15#post-716037

Unfortunately i think i missed something because my custom fields are well displayed, but, not protected !

i integrated this code to the template file :
<?php
if ( function_exists( 'wpmudev_ppw_html' ) ) {
$contrat = the_custom_field( 'contrat' );
$price = '0.01';
$description = 'test';
global $ppw;
if ( !is_object( $ppw ) )
return;
$my_custom_field_ppv = $ppw->content( $contrat );
// Echo the content from our custom field after we pass it through PPV
echo $my_custom_field_ppv;
}
?>
Can you help me and say to me what i missed, because i really feel dumb right now !

Thank you !
Nicolas