Formal — to staff
Train · Station · Lost · Found
昨日、〇〇線で黒い傘を忘れてしまったのですが、届いていませんか? — I left a black umbrella on the 〇〇 line yesterday. Has it been turned in? (Train · Station · Lost · Found, Formal — to staff, JLPT N4)
You
昨日、〇〇線で黒い傘を忘れてしまったのですが、届いていませんか?
きのう、まるまるせんでくろいかさをわすれてしまったのですが、とどいていませんか?
I left a black umbrella on the 〇〇 line yesterday. Has it been turned in?
Romaji: Kinō, marumaru-sen de kuroi kasa o wasurete shimatta no desu ga, todoite imasen ka? / Reply Romaji: O-wasuremono desu ne. Tokuchō o kuwashiku oshiete itadakemasu ka?
Reply
お忘れ物ですね。特徴を詳しく教えていただけますか?
おわすれものですね。とくちょうをくわしくおしえていただけますか?
A lost item, is it? Could you please tell me more about its characteristics?
Gesture & etiquette
Slightly bow, show frustration/concern (but politely).
Be as specific as possible about the item, time, and location to increase chances of retrieval. Replace 〇〇 with the actual train line name.