Closing the thread on this. I went to COSTCO today and asked them to cancel it out. They were very understanding, and stated they will cancel it for me. Also, in case if I get any further note/queries on this ticket, I can contact them.
Additional Info for other COSTCO people out there - If you think you will be getting over the stipulated 3 hours, contact the helpdesk inside the store, and they will manage it at the backend. You won't be having the hassle of getting a ticket.
A heartfelt Thank You to everyone in this forum for their help and support.