Your purchase order has been referred to me. I note that the third item on the order is(quantity) of our (product) at a price of $------- each.
While we appreciate an order of this size, the terms and conditions on page ___ of our catalog clearly specify that overseas orders are accepted with full payment in advance, and with an amount sufficient to cover shipping.
We are therefore returning your purchase order. Please resubmit your order with either a sight draft, or an irrevocable letter of credit. We anticipate the shipping charges to be in the neighborhood of $------ (currency) per flag ordered.
Thank you for your order and we look forward to serving you in the near future.