Ahoy there, Dawn! Welcome aboard!
Disney Cruise Line should automatically enroll you in the
Castaway Club when you complete your first sailing. If you have completed your first eligible sailing, double-check to see if you are already considered a Silver Castaway.
I added the word "eligible" in there because
some sailings do not count towards your Castaway Club status. If your sailing seven years ago was booked with certain special fares (vendor or media, for example), if it was a complimentary sailing, or if you happened to be a Disney Cast Member traveling for work, that sailing would not be considered eligible.
If you've double-checked your Castaway Club status, confirmed you weren't on a special fare voyage, and still don't see your status as Silver Castaway, it's time to
bring in the experts. You can
email Disney Cruise Line, and give them the date of your cruise and other relevant information - your name, birthdate, if your last name was different then, include that. You can also
call and speak with a cast member, who can walk you through the process, find your missing cruise, and hopefully bump you into the Castaway Club!
I hope you are soon in shipshape, Dawn. We thank you for sailing on in with your question!
Anna