I also agree the noise is entirely unacceptable.
But the real shame is that they were not able to do anything to fix during your entire cruise. I always feel bad for people who leave a ship with an unresolved problem, because there is no way to change what happened. In my opinion every problem of that nature should be made a first priority and fixed as soon as humanely possible - even if they had to fly in a new door.
I also agree that you deserve a refund or at the very least a do-over in a nicer room at no cost.
Completely unacceptable, especially for a company like Cunard!