gistfile1.php

    $client = new ZendeskAPI($subdomain, $username);
    $client->setAuth('token', $token); // set either token or password

    $search_query = "type:ticket status<solved order_by:updated_at sort:desc fieldvalue:" . $from;

    try 
    {                    
        $results = $client->search(array('query'=>$search_query));
        
        if ( (int)$results->count > 0) {

            $ticket = $results->results[0];
            $ticket_id = (string) $ticket->id;
            
            $client->ticket(array($ticket_id))->update(array(
                'comment' => array(
                        'public' => true,
                        'body' => $body
                        )
            ));
        }        
        else {

            $newTicket = $client->tickets()->create(array (
            	'description' => $body,
                'subject' => substr($body, 0, 80), 
    	        'requester_email' => $username,
                'custom_fields' => 
                    array(
                        'id' => $ZD_FIELD,
                        'value' => $from                    
                    )
            ));
        }
    }
    catch (Exception $e) 
    {
        $debug = $client->getDebug();
        echo $debug->lastResponseCode;
    }