public function getVoiceConsumptions($service, $billingAccount, $params = null)
    {
    	$paramsString = "";
    	if (!$service)
            throw new BadMethodCallException('Parameter $service is missing.');
        if (!$billingAccount)
            throw new BadMethodCallException('Parameter $billingAccount is missing.');
        if ($params != null && is_array($params) && count($params) > 0)
        {
        	$paramsString = "?";
        	if (array_key_exists('creationDatetime.from', $params))
        	{
        		$string = $params['creationDatetime.from'];
        		if ($params['creationDatetime.from'] instanceof \Datetime)
        			$string = $params['creationDatetime.from']->format("Y-m-d\TH:i:sP");
            	$paramsString .= "creationDatetime.from=".urlencode($string);
        	}
        	if (array_key_exists('creationDatetime.to', $params))
        	{
                $paramsString .= "&"; 
        		$string = $params['creationDatetime.to'];
        		if ($params['creationDatetime.to'] instanceof \Datetime)
        			$string = $params['creationDatetime.to']->format("Y-m-d\TH:i:sP");
            	$paramsString .= "creationDatetime.to=".urlencode($string);
        	}
        	if (array_key_exists('destinationType', $params) && in_array($params['destinationType'], array('landline', 'mobile', 'special')))
            {
                $paramsString .= "&";
            	$paramsString .= "destinationType=".$params['destinationType'];
            }
        	if (array_key_exists('planType', $params) && in_array($params['planType'], array('outplan', 'priceplan')))
            {
                $paramsString .= "&";
            	$paramsString .= "planType=".$params['planType'];
            }
        	if (array_key_exists('wayType', $params) && in_array($params['wayType'], array('incoming', 'outgoing', 'transfer')))
            {
                $paramsString .= "&";
            	$paramsString .= "wayType=".$params['wayType'];
            }
        }
        try {
            $r = $this->get('telephony/' . $billingAccount->getBillingAccount() . '/service/' . $service . '/voiceConsumption' . $paramsString)->send();
        } catch (\Exception $e) {
            throw new TelephonyAccountServiceException($e->getMessage(), $e->getCode(), $e);
        }
        return $r->getBody(true);
    }