My experiences with Disney Cruise Line regarding this issue.
As more guests on the Disney Cruise Line have run into this problem, they have assigned 1 agent to deal with us all. She says that they did everything they could and that there isn't a problem, according to the CBP. There is nothing more they can do.
The experience we (me and the other guests) with both DCL and the CBP have: you have to keep calling. If an e-mail at the CBP isn't picked up within their time limit (which is 6 working days, I think), it gets filed without being handled.
Last week I called the CBP again and they initially wanted me to send them a statement from the cruiseline that I had left the cruise. Which I had already send them with a copy of my boarding pass for my flight home.
So then they asked to e-mail them some general details, name, DOB, vessel etc. and a copy of my passport. As soon as the 6 working days are over, I'll call them again.
One guest has now booked a new transatlantic cruise, WBTA, to handle the issue when they arrive in the US. Another one got a phone confirmation from the CBP that in the system they can see it's all good, so she booked another holiday in the US, and is going to hope for the best.