If you think you've returned something that's still checked out on your card, you can tell the library about the problem by using the Report Item Returned form.
After you have reported the item as returned, if the library doesn't find it on the shelf, or find out that it is checked out to someone else, you will be given a 2 month grace period to try and find it.
During that time, both you and library staff will look for the missing item. If it's not found after 2 months, you will be billed for the item’s replacement cost, plus any late fees before it was reported missing. If the item is found, late fees will be charged up to the time the item was returned.