I finally have bounced emails coming in for campaigns, and the campaing log is setting activity_type accordingly, however records are not being updated (i.e. invalid_email is not being flagged). I've worked out a query to update all, and am trying to simply add an Update Invalid Email link in the head of Contacts/ListView.html. Why won't this work????

I tried adding the following to ListView.html
HTML Code:
<?php
switch ($_GET['update']) { 
case "contacts"; 
$sql = 'UPDATE contacts, campaign_log' 
        . ' SET contacts.invalid_email=1' 
        . ' WHERE contacts.id=campaign_log.target_id' 
        . ' AND campaign_log.activity_type="invalid email"'; 
mysql_query($sql); 
break; 
} 
?>
<!-- BEGIN: main -->
<table cellpadding="0" cellspacing="0" width="100%" border="0" class="listView">
<tr><td colspan="10" align="right">
<a href="index.php?update=contacts&module=Contacts&action=index">
Update Invalid Email
</a>
</td></tr>
... which returns me to the appropriate page without errors, but does not update the reocords in the db. NO JOY.
What have I got wrong?
What am I missing?
Better still, how would I alter ProcessBouncedEmails.php to flag the records???