I will add another problem when dealing with "Agents". We always booked our cruises through the line itself and not an agent and most were transatlantics.
A couple of cruises ago we decided to use an Agent to see if it would be easier..WRONG..In one case the cruise offered a lower price and when that happens you can get the lower price by asking. We pointed out the lower price to the agent and she first said it was not available, (we knew it was) and then it was too late, (not true) and then she would try. It is critical to know that once you go through an Agent the Cruise Line will not talk to you. You have to go back to the Agent. We had to go to the Owner of the Agency to get them involved and after a ton of calls and work we finally were able to get the credit. Never again..The problem is that you can no longer deal with the cruise line and if the Agent is reluctant to work for the credit, is not dedicated etc. you are at their mercy.