They have also regularly emailed out information with "vaccination and testing requirements" whenever there has been a change or X number of days before the cruise. The OP will have had this too. It will have clearly been listed in there.
Welcome to CC!
Sadly, their policy is quite clear on the website. The policy for TA's is different to cruising round Europe. I don't see you getting a refund or credit.
And just like that ... an email from FedEx has arrived today for a package that has been shipped from Sunrise,FL to the UK today.
Looks like it's finally on the way 😄