Postal Act Article 33

Once compensation is effected because of the loss of a mail item, if all or part of the mail item is subsequently found, Chunghwa Post may notify the recipient of the indemnity to return all or part of the compensation and claim the originally posted mail item within three months after receipt of notice.
中文原文 郵政法第33條
中華郵政公司於履行補償後,發現原寄郵件之全部或一部時,應通知受領補償者,得於收到通知之日起,三個月內,退還補償金之全部或一部,請求交付該項發現之原寄郵件。

English translation for reference only; the Chinese text prevails. Not legal advice.