Hi, Bill!
Don't give up just yet! Because there is a penalty for being a "no-show" guests will cancel their reservations if they cannot attend. Make sure you have the My Disney Experience app downloaded on your smart phone, and keep checking! My last vacation I was able to book a prime time reservation at Crystal Palace the day before, and I had been checking for weeks.
Cinderella's Royal Table is one of the hardest reservations to secure, but you never know when a bit of pixie dust will come your way and a table opens up. You can also ask at the podium to see if they have any last minute tables available. You just never know.
If you are looking at dining with the Princesses, you might also want to check out
Akershus Royal Banquet Hall in Epcot. Here, you will have several of the lovely Princesses on hand to welcome you for breakfast, lunch, or dinner. Breakfast at this location is my personal favorite. (Shhh, don't tell Cinderella, but I actually like Akershus better than dining in Cinderella Castle!)
Sending magical wishes your way that you get the opportunity for a royal feast with the Princesses!
Cathy