Just a follow up here. If you didn't get an "email survey" and wish to make comments/suggestions about your cruise you can do it
HERE.
Select "Already Sailed" on the button and fill in the info.
Another option is to email your comments to;
guestcare@carnival.com
Make sure to include your booking # and sail date.
The current email Comment Card/Survey system is being reviewed from what I've heard. So hopefully it will get easier and more consistent with getting the surveys.
Dwayne