Hook to modify invoice description

[consul]

Hi all,

I'm trying to create a hook to add the name of the registrant of a domain in the description of the invoice, so as to obtain a description of this type:

 

Domain Registration - domainame.com - 1 Year/s (19/08/2016 - 18/08/2017) - ACME Ltd

 

<?php
function invoice_domain_registrant($vars) {
   $result = full_query("SELECT id, description, (SELECT (SELECT tblcontacts.companyname FROM tblcontacts WHERE id = tblorders.contactid) FROM tblorders WHERE userid ='".$vars['userid']."' AND invoiceid='".$vars['invoiceid']."') AS registrant FROM tblinvoiceitems WHERE invoiceid='".$vars['invoiceid']."'");
   while($data = mysql_fetch_array ($result))
       if($data['registrant'] !== NULL) // Add Company Name of contact of client
           update_query("tblinvoiceitems", array("description" => $data['description']." - ".$data['registrant']), array("id" => $data['id']));
} else {
$result = full_query("SELECT id, description, (SELECT (SELECT tblclients.companyname FROM tblclients WHERE id = tblorders.userid) FROM tblorders WHERE userid ='".$vars['userid']."' AND invoiceid='".$vars['invoiceid']."') AS registrant FROM tblinvoiceitems WHERE invoiceid='".$vars['invoiceid']."'");
while($data = mysql_fetch_array ($result))
       if($data['registrant'] !== NULL) // Add Company Name of client
           update_query("tblinvoiceitems", array("description" => $data['description']." - ".$data['registrant']), array("id" => $data['id']));
}
add_hook("InvoiceCreationPreEmail", 1, "invoice_domain_registrant");

 

I do not understand what is the error, but the description does not change...

 

Thank you.