The cruise line didn't want to talk to us. They kept telling us to contact our TA, but after much time, effort, and persistence, we were able to get the cruise line to give us the information we needed to then get our TA to give us the information we needed, to fix the latest and most serious issue ourselves directly with the cruise line.
At this point, it is not worth the trouble and aggravation to change the TA for this cruise (judging from all the helpful posts on this thread. Thank you everybody.) But we have found a different TA for any future bookings.