Помощь по Litepanel

<?php
class resultController extends Controller {
    public function index() {
        $this->load->model('users');
        $this->load->model('invoices');
        
        if($this->request->server['REQUEST_METHOD'] == 'POST') {
            $errorPOST = $this->validatePOST();
            if(!$errorPOST) {
                $ammount = $this->request->post['wOutSum'];
                $invid = $this->request->post['wInvId'];
                $signature = $this->request->post['wSignature'];
                
                $invoice = $this->invoicesModel->getInvoiceById($inv_id);
                $userid = $invoice['user_id'];
                
                $this->usersModel->upUserBalance($user_id, $ammount);
                $this->invoicesModel->updateInvoice($inv_id, array('invoice_status' => 1));
                return "OK_$inv_id\n";
            } else {
                return "Error: $errorPOST";
            }
        } else {
            return "Error: Invalid request!";
        }
    }
    
    private function validatePOST() {
        $result = null;

        $mrh_id = $this->config->wp_mrh_id;
        $mrh_secret_key = $this->config->wp_mrh_secret_key;

        $out_summ = $this->request->post['wOutSum'];
        $inv_id = $this->request->post['wInvId'];
        $signature = $this->request->post['wSignature'];
        $crc = strtoupper($signature);
        $my_crc = strtoupper(md5("$mrh_id:$out_summ:$inv_id:$mrh_secret_key"));

        if(!$this->invoicesModel->getTotalInvoices(array('invoice_id' => (int)$inv_id))) {
            $result = "Invalid invoice!";
        }
        elseif($crc != $my_crc) {
            $result = "Invalid signature!";
        }
        return $result;
    }
}
?>

<?php
class failController extends Controller {
    public function index() {
        $out_summ = (float)$_REQUEST["wOutSum"];
                $inv_id   = (int)$_REQUEST["wInvId"];
                return "<center>Ошибка! Оплата заказа $inv_id прошла не успешно!<br/><a href='/'>Вернуться в панель управления</a></center>";
    }
}
?>

<?php
class successController extends Controller {
    public function index() {
        $out_summ = (float)$_REQUEST["wOutSum"];
        $inv_id   = (int)$_REQUEST["wInvId"];
        return "<center>Оплата заказа $inv_id прошла успешно!<br/><a href='/'>Вернуться в панель управления</a></center>";
    }
}
?>