We were recently on a Celebrity cruise and received an e mail inviting us to bid for an upgrade. We didn't do so but there we met some people who had received a free upgrade. So Cunard may well follow suit if they have the cabins available. This couple did not discover that they had been upgraded until embarkation.
Contact them via Facebook. My husband had been trying for weeks to get a response by e mails and, on one occasion a phone call which cost $60 during which he was passed from pillar to post without actually speaking with anyone. He received a call back within 10 mins after posting on Facebook.
It is extremely unusual, but they did do lunch in Blu on one occasion when we were not able to stop at a port. I don't know if this was a one off or if it always happens when a port is missed as, so far, this has only happened to us that once.