We are very sorry but we had a mix-up in our inventory software and only had
one in stock.
We are calling (メーカー名) today to see how quickly we can get more in stock.
If we can get more, we can ship them as a gift to hopefully avoid extra
charges.
If you would like to be refunded, please let us know.
申し訳ありません。「追加費用(関税?)の請求を贈呈品」の部分の訳文を「追加費用(関税?)の請求を避けるため贈呈品」に修正してください。