public JsonResult InvokeWithdraw(long accountNumber, decimal amount, string currency)
        {
            var result   = ur.InvokeWithdraw(accountNumber, amount, currency);
            var withdraw = new BalanceViewModel
            {
                AccountNumber = result.AccountNumber,
                Balance       = result.Balance,
                Currency      = result.Currency,
                Successful    = result.Successful,
                Message       = result.Message
            };

            return(Json(withdraw, JsonRequestBehavior.AllowGet));
        }