This is the first post I've read about an ecodiesel having a fueling issue. There are plenty of complaints for the gas versions though. Are you sure you have the 33 gallon tank? Might want to first verify that on the build sheet. Just enter your VIN and click the search button.
fcacommunity.force.com
I'd want a witness for the next fill up so I'd probably drive it until the gauge reads nearly empty, then take it in to the dealership and ask to have a tech to ride with you to fill it so they can see it happen. I live in a small town with a small town dealership so they are accommodating for that sort of thing. You may need to make an appointment for that if your dealership is always super busy.
