I love our National Library of Singapore. The book collection is superb. The atmosphere in most places are conducive for reading, meeting, and working on assignments.
I can renew books and check catalogue online. I can keep tab of my borrowings, set reminders for impending overdue etc.
However, there is one flaw in the system. If I forget to renew my books on time, the system will prevent me from renewing them (even though I was allowed to do so a day before overdue). The penalty system kicks in by commencing charging of overdue cost and at the same time penalises users from renewing, which is very unfair. IMHO, renewal option should be given to user to prevent further overdue charges (esp. considering that the book is still needed by user).
I believe it could be a computer bug. If user has unpaid overdue, he/she will be prevented from both borrowing and renewal, hence the only way is to physically be at the library to return the book(s) or request renewal of book(s) at the counter after overdue payment.
So for now, if you forget to renew on time, you have to return the book ASAP and pay $0.15 per book per day. That is the penalty for not renewing on time. Bummer.