Something similar happened to me... not with a
travel agent, but a
DCL cast member. I called to have a 4th person added to my parent's stateroom. The cast member cancelled their reservation and rebooked a different cabin without mentioning to me. Evidently, there was no room in the lifeboat for that 4th person, so a new cabin had to be selected. They are no longer next to us. Also, I had them checked in online and all of their excursions selected. All of that disappeared. PLUS- we were all on main dining. Since the cruise was sold out (thanksgiving), they were now on second seating!!! It became a brand new reservation!
I had to recheck them in again (a much later PAT than us - Thank God I took the Disney Transfers, so they will be let in the terminal with us), and rebook all their excursions. When I called back to complain (I only realized this AFTER I checked our ressies on the Disney site), they told me about the lifeboat situation ( I would have switched cabins anyway to get that 4th person in), and had guest services work on getting us all back together on main dining... which they did.
I just felt frustrated all my plans were screwed up. My kids are upset they are no longer next to their grandparents, but I can't let it ruin my vacation.
Please let us know how it works out for you!!! Good Luck!