I agree with Mike. On our next cruise, I have $5000 of non-cruise related expense all prepaid and nonrefundable.
I would be on the phone with the TA and Oceania demanding that they put you back on. Let them bump somebody else who booked after the ship was sold out.
SS Norway (12 times) '85 - '97; Radiance OS 06/01; Island Princess 11/04, Grand Princess 11/04/05, Golden Princess 7/21/06, Golden Princess 2/24/07, Explorer of the Seas 12/23/07, Island Princess 11/15/08