Могу предложить такой вариант:"Dear All,I am writing to you in respect of my order (или orders - если будете писать по нескольким заказам) number ____ (укажите номер/номера заказов).I have the inquiry regarding the delivery cost of my package.  As I understand I was overcharged for delivery of my package (или packages).The delivery cost for Russia is 24.95 pounds (for 2 kg) plus 2 pounds for each additional kg. My package was __ kg (вес Вашей посылки) as indicated on package's accompanying documentation. This means that the delivery cost of my package should be ____ pounds (24.95 punds + __ kg*__ = __ pounds). However, actual delivery cost which was deducted from my card was ___ pounds (скока с Вас реально взяли за доставку). Please make an adjustment and refund the overpaid ___ pounds to me.Thank you in advance for you prompt response and action.Regards,Ваше имя"Только у Вас даже еще меньше должны были за посылку взять. Вес 5,7 кг. Итого: 24.95+4 кг*2+ 32.95 фунта.