Web service not response result in client - php

Question

i try test web service with nusoap and php. And here is my code:
Server.php:
require_once ("lib/nusoap.php");
$URL= 'http://myexample/service.php';
$namespace = $URL.'?wsdl';
$server = new soap_server();
$server->configureWSDL("topUsers",$namespace);
$server->register("getTopUser");
$server->soap_defencoding = 'UTF-8';
$server->decode_utf8 = false;
$server->encode_utf8 = true;
function getTopUser(){
$conn = mysql_connect('localhost','root','test#123') or die(mysql_error());
mysql_select_db('test',$conn)or die(mysql_error());
mysql_query("SET charactor_set_results=utf8",$conn);
mysql_query("SET NAMES 'utf8'");
$query = mysql_query("SELECT * FROM player ORDER BY money DESC LIMIT 0,10",$conn) or die (mysql_error());
while($row = mysql_fetch_array($query)){
$data[] = array(
'userid'=>$row['userid'],
'username'=>$row['nick'],
'money'=>$row['money']
);
}
return $data;
}
if(!isset ( $HTTP_RAW_POST_DATA ))$HTTP_RAW_POST_DATA = file_get_contents ('php://input');
$server -> service ( $HTTP_RAW_POST_DATA );
Client.php:
require_once("lib/nusoap.php");
$url = 'http://myexample/service.php?wsdl';
$client = new nusoap_client($url);
$reponse = $client->call('getTopUser',array());
$client->soap_defencoding = 'UTF-8';
$client->decode_utf8 = false;
//$client->decode_utf8 = false;
$err = $client->getError();
echo $err;
echo $reponse;
echo '<h2>Request</h2><pre>' . htmlspecialchars($client->request, ENT_QUOTES) . '</pre>';
echo '<h2>Response</h2><pre>' . htmlspecialchars($client->response, ENT_QUOTES) . '</pre>';
echo '<h2>Debug</h2><pre>' . htmlspecialchars($client->debug_str, ENT_QUOTES) . '</pre>';
And here is result of my code:
2015-08-27 03:14:09.228293 nusoap_parser: parsed successfully, found root struct: 2 of name getTopUserResponse
2015-08-27 03:14:09.228530 nusoap_client: sent message successfully and got a(n) string
return=string(0) ""
I don't know i wrong somewhere? Somebody help me, please. Thanks!