We have verified you order ●● and buyer's messages related to this order. Regarding a payment of duties according A policy (Agreement) a purchase price is the total gross amount payable or paid by a buyer for Your Product (including taxes and customs duties). The price stated by seller for products is inclusive of any VAT, customs duty, excise tax or other tax that you may be required to remit in connection with such sale.
In this situation we suggest you to contact a buyer and try to resolve this issue amicably. In this case seller should refund a duty payed by customer.
この状況においては、バイヤーに連絡をとって本件を友好的に解決するように努めることをご提案します。この場合セラーは顧客が支払った税金を払い戻すべきでしょう。
現在の状況ですと、購入者様へコンタクトをとり平和的な解決をされるようお勧めいたします。今回の場合は販売者様が顧客の支払った税金を返金されるのがよろしいかと思われます。