So a bit of an update and more details.
Yes, my original cruise was booked through a UK agent. I've never received a comp crusie and didn't know when and where we wanted to go with it.
I explained it to the NextCrusie rep, she created the book later, knowing we wanted to apply the comp to it, and even explained the best way to do it. She's the one who applied to the out TA and said that was the way to do it.
Last night I finally got to someone in the UK team who was able to help. After an hour of talking to them, they applied the comp to the next cruise bookings (we had two), and the cruises showed up in our planners last night.
We then booked all our flights.
Well, today, they called me up and said they are canceling all the reservations because the Next Crusie certs are still attached to our TA and they can't fix it.
I called the TA (Cruise.co.uk) and they said they don't see them because there's no booking against them and there's nothing they can do.
RC then said I have to work to convince C.co.uk to call them and release the certs even though RC set them up in error.
So now I'm sitting here, no cruise, 4 non-refundable flights, and no idea if it'll be sorted.
Regretting all the money I've spent with RC over the past 4 years.