The lady should take her coffee card to a bar and request a mug. If that does not work, go to guest services and tell them. You need access to problem solvers to fix problems on cruise ships, and basically a waiter is not in any position to go outside of his own realm to fix anything.
But I give him credit for trying.
For sure KUDOS to the waiter for trying to assist. His "superior" should have never embarrassed him or the guest.
Sure she won't pursue the silly mug, and no doubt it will be stored in the back of her mind as we have more and more fun.