public function getUserData()
  {
    $username = $this->_username;
    $this->_requestUrl = self::USER_DATA_URL.'?username='.$username;
    $this->executeGet();
    
    if ( $this->_responseInfo['http_code'] == self::HTTP_CODE_OK ) {
    	 $responseObject = json_decode($this->_responseBody);
    	 return $responseObject->UserData;
    	}
    	
     throw new AfricasTalkingGatewayException($this->_responseBody);
  }