Just call them between midnight and 4 AM and tell them you "just don't want the card anymore" you want to "simplify your number of cards" or something.

Customer retention will be closed, you'll most likely get a contracted customer service agent from abroad. All will be over in less than 2 min! Let us know about your experience!

P.S. Though if you are from Hawaii (as your sn might suggest) you'll want to wait until midnight EST. ;-)