1回目に荷物を送った時、あなたが不在のため受け取りできず、その荷物は日本へ戻ってきました。
しかし、実際に荷物を発送しているため、送料が6000円かかっています。
この時の送料6000円は(もういちど商品を送っても送らなくても)あなたが支払う必要があります。
2回目も実際は6000円かかりましたが、楽天キャンペーン適用によりあなたの負担は1000円のみです。
つまり、あなたが支払うべき金額は、商品20000円+1回目送料6000円+2回目送料1000円で、「27000円」になります。
However, because I really did ship it it cost me 6,000 yen for the shipping.
You need to pay the shipping from that time (regardless of if I send the item again or not).
The second time it also cost 6,000 yen but because of a Rakuten campaign it only cost you 1,000.
In short, the amount that you owe me is 20,000 yen for the item + 6,000 yen for the first time shipping and 1,000 yen for the second time, which comes to 27,000 yen.
I actually paid the shipping charge of 6000 yen. You have to pay this charge regardless of whether I send it again or not.
The second shipping charge was also 6000 yen. However, by using Rakuten Campaign, you have to pay only 1000 yen.
That is, the total amount of the charge you have to pay is 27000 yen: 20000 yen (item) + 6000 yen ( first shipping charge) + 1000 yen (second shipping charge) = 27000 yen.
However, I shouldered at 6,000 yen because I actually shipped the item to you.
You should shoulder this shipping charge, even I shipped again or not, because this is not my fault.
When I shipped at the second time, the shipping charge was supposed to be 6,000 yen again but Rakuten’s sales promotion campaign cut it to 1,000 yen.
Therefore, the total amount you owed to me is 27,000 yen which is the summation of the price of item at 20,000 yen, shipping charge at first time at 6,000 yen and shipping charge at second time at 1,000 yen (20,000 + 6,000 + 1,000 = 27,000 yen).
However, shipment was happened actually, and the postage took 6000 JPY.
You need (even without receiving it but the goods was once) to pay 6000 JPY for shipping at this time.
And it took 6000 yen again for the second time, however your charge is only 1000 JPY by Rakuten campaign application.
In other words, ¥ 20,000 for products + 2nd Shipping cost 1000 yen + 1st postage ¥ 6,000, so you should pay 27,000 JPY in all.