Last week I went to a Post office that I rarely go to and bought some envelopes to send a package overseas but I forgot to take my change (38yen).
That evening the Post office called my home to let me know that they had my change and they would keep it for me until I picked it up.How did they find me? From the return address on the package I had sent! Today (almost a week after sending the letter) I went back to that Post office and retrieved my change.
The very kind woman behind the counter immediately retrieved my change from an envelope they had stored in the back office and apologized for causing me trouble and bothering me at home.