OBC - On board credit.
I definitely couldn't have stayed in the cabin with that noise. In June I had a problem with the wind whistling around my balcony door. Tried the usual fix of slamming it and locking until day 2 when I discovered air coming in around the base of the door. The solution - when the ship was in motion (and this trip included 2 TAs) the room steward and I kept the long bolster pillow from the bed wedged against the door. No more noise.
Yes, your trip was obviously ruined but don't let it continue to eat at you. I personally would continue to pursue it.
Sun Princess (2 times), Mississippi Queen, Dawn Princess, Coral Princess (2 times), Regal Princess, Grand Princess, Diamond Princess, Maasdam, QM2 (15 times)