I will admit that I am someone who is careless with his own belongings. There are times when I just simply forgot my stuff back in the classroom.
There are lucky times when my stuff was just left there without being touched. Other times, it would be simply gone after I realized that it was not with me for a few days.
If that happened to you, what should you do?
In case you do not know, you can first check out the places in which you last remembered the item is with you. For every lecture halls or study spaces, there is actually space where you will see the Lost & Found items are allocated. Check them out and you might be able to find what you have lost.
Another idea would be to get help. You can try visiting the Security office which is right beside the Student Registry Office. I managed to get back my lost bottle in that method, so I think that it is reliable to get help.