Regulations for Administration of Mobile Broadband Businesses Article 76

The operator shall retain the telecommunications records for at least a six-month period.The operator, in response to the subscriber's own inquiry request, shall supply its communications records retained per the foresaid stipulation.
中文原文 行動寬頻業務管理規則第76條
經營者對於通信紀錄,應至少保存六個月。
經營者因使用者本人查詢之申請,應提供依前項規定保存之通信紀錄。

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