Paying my website user with paypal MassPay Paypal - php

Question

I am Trying to Pay users with Paypal MassPay API from my website.
public function PPHttppost($methodName,$nvpstr){
$setting = $this->globalsetting();
// Set up your API credentials, PayPal end point, and API version.
$API_Username = $setting->paypal_api_username;
$API_Password = $setting->paypal_api_password;
$API_Signature = $setting->paypal_api_signature;
$API_Environment = $setting->paypal_mode;
$API_Endpoint = "https://api-3t.sandbox.paypal.com/nvp";
$API_Version = '116.0';
if('sandbox' === $API_Environment || 'beta-sandbox' === $API_Environment){
$API_Endpoint = "https://api-3t.$API_Environment.paypal.com/nvp";
}
$version = urlencode($API_Version);
//set curl paramaeter
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $API_Endpoint);
curl_setopt($ch, CURLOPT_VERBOSE, 1);
//Turn of server and pakagemanager
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
//set the API operation,version,API signature in requrest
$nvpreq = "METHOD=$methodName&VERSION=$version&PWD=$API_Password&USER=$API_Username&SIGNATURE=$API_Signature&$nvpstr";
//set the request as POST field for curl
curl_setopt($ch, CURLOPT_POSTFIELDS, $nvpreq);
//get the response from server
$httpResponse = curl_exec($ch);
if(!$httpResponse){
exit("$methodName failed:".curl_error($ch).'('.curl_errno($ch).')');
}
//Extract the response details
$httpResponseArray = explode('&', $httpResponse);
$httpParsedResponseArray = array();
foreach ($httpResponseArray as $i=>$value){
$tmpArray = explode('=', $value);
if(sizeof($tmpArray) > 1){
$httpParsedResponseArray[$tmpArray[0]] = $tmpArray[1];
}
}
if((0 == sizeof($httpParsedResponseArray)) || !array_key_exists('ACK',$httpParsedResponseArray)){
exit("Invalid HTTP Response for POST request($nvpreq) to $API_Endpoint.");
}
return $httpParsedResponseArray;
}
$nvpstr = "RECEIVERTYPE=EmailAddress&EMAILSUBJECT=Your withdraw request was processed&L_EMAIL0=seller#gmail.com&L_AMT0=$amt&CURRENCYCODE=$currency";
public function doMassPay($nvpstr){
$httpParsedResponseArray = $this->PPHttppost('MassPay', $nvpstr);
pr($httpParsedResponseArray);exit;
}
When, I call MassPay api of paypal , it returns me success
Array
(
[TIMESTAMP] => 2014%2d09%2d12T07%3a18%3a12Z
[CORRELATIONID] => c4c61215cdd72
[ACK] => Success
[VERSION] => 116%2e0
[BUILD] => 12786467
)
but when I check my account log, it shows receptitant was unable to accept ammount, transaction was denied.
I checked it with different test account, everytime it returns same response. Can anyone guide me where and what I am doing wrong? I am using cakephp framwork and using no library for calling Paypal API.