src/Didww/API2/CDRInvoice.php
public function load()
    {
        $response = $this->call('callhistory_invoices', array(
            'customer_id' => $this->getCustomerId(),
            'from_date' => $this->getFromDate(),
            'to_date' => $this->getToDate()
        ));
        $this->fromArray($response);
        return $this;
    }
public function load()
    {
        $response = $this->call('callhistory_invoices', array(
            'customer_id' => $this->getCustomerId(),
            'from_date' => $this->getFromDate(),
            'to_date' => $this->getToDate()
        ));
        $this->fromArray($response);
        return $this;
    }
load amount from API2
@return \Didww\API2\CDRInvoice