For those of you who are attacking the original poster, I am in a similar situation apparently. My cruise on the Star was cancelled. When I went to book a substantially similar cruise on the Sun...same number of days and same ports, the cost is approximately $4,000.00 more than what I had booked for. No option to change my booking to another ship or anything, just straight cancellation and an expectation to pay an extra $4,000.00 apparently. I was offered and have a $100.00 future cruise credit which is in my account as per the cancellation e-mail I received.
I don't think that is very satisfactory.