Rules Governing the Business of Electronic Stored Value Card Issuers Article 9

If an issuer collects certain amount in advance from the cardholders and promises to refund it later, except for money stored in the electronic stored value card which shall be handled in accordance with Articles 18 ~ 20 of the Act, the remainder of collected amount shall be declared trust in full or fully guaranteed by a bank.
中文原文 電子票證發行機構業務管理規則第9條
發行機構如有事先向持卡人收取,並約定返還之款項,除儲存於電子票證之款項應依本條例第十八條至第二十條規定辦理外,其餘款項應全部交付信託或取得銀行十足履約保證。

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