以前インボイスには必ず送料を含めるようにとお知らせしましたが、誤りでした。
顧客に請求しない送料の記載は不要です。請求しない送料を含めると、請求金額と合わなくなってしまいます。
誤った情報をお伝えして申し訳ございません。
I informed what you should include shipping charge into the invoice before, but it was wrong.
You don't need to write the shipping charge which you don't ask customers to make a payment.
If you include shipping charge which you don't ask them to pay, the amount is different from the amount in the invoice.
I am sorry for providing the wrong information.