Just the hard facts
---I hope the OP doesn't take what I'm going to say in a way that may mean I'm harsh, uncaring, etc. but you have to be realistic--maybe this was their first cruise and they simply haven't learned yet---
Here's something to remember---people who work on a cruise ship see thousands of different people on a weekly basis. No matter their job, they, for the most part, are friendly as that's part of their job. When the cruise is over, you leave the ship and go home. As soon as the ship is cleared, there's another load of several thousand people coming on. The bar stool you occupied on your cruise last week has a new rear end and face on it this week. The table in the dining room you ate at has a new group of people. Your lounge chair by the pool has a new body on it. In other words, you're basically history as you were there last week--- your cruise is over and a new shipload of people have taken your place.
Next week, this group's week will be over and they will be history as a new group has replaced them so around it goes.
In a lot of cases, the crew doesn't want to hear from a past passenger, for several reasons I could state but won't.
Like Trip said, years ago RCCL would give out a list of the passengers with their names and hometowns. But, that's all changed.
To cut it short, if you want to try to contact someone, send a letter or message to the cruise line's headquarters and see if they will pass on any info to the particular crew person, which is very doubtful.
Just the hard facts--no more, no less!