// GET: Billing/Details/5
        public ActionResult Details(string id)
        {
            Bill bill = billingManager.returnBill(Convert.ToInt32(id));

            string customerName = customerManager.getCustomerByID(bill.CustomerID).getName();

            ViewBag.Title = "Bill Details";

            ViewBag.CustomerName = customerName;

            return(View(bill));
        }