[Translation from English to Japanese ] I called the United States Postal Service and told them about the dilemma wit...

I called the United States Postal Service and told them about the dilemma with the customs. They are going to contact them and get back to me. I also checked this website: http://www.customs.go.jp/english/summary/prohibit.htm and it doesn't say medical supplies anywhere. Maybe you can call the Japan Customs and tell them it doesn't say you can't ship medical supplies.

米国郵便局に連絡し、税関での問題について説明しました。郵便局側は税関に連絡し、結果を知らせてくれるそうです。また、下記のウェブサイトを確認しましたが、医療用品について記述がありませんでした。http://www.customs.go.jp/english/summary/prohibit.htm
あなたが日本の税関に連絡して、医療用品の輸出入ができないとは書いてないと伝えてみるのはどうですか。