Example of Formal Business letter
I am writing to apologize about keeping books that I borrowed from the college library 3 days longer than it is acceptable.
I have found myself in this unpleasant situation for a reason. My close relative was very sick and I had to go visit him at the hospital. I intended to return the books immediately after I get back to the college, but unfortunately I left the books on a train on my way from the hospital to the library. It will take me about two days to get them back from “Lost and Found” department at the train station.
I understand that other students may need those books and deeply apologize for the inconvenience. I will try to return the books as soon as possible. Please don’t revoke my library privileges, I promise that it will never happen again.