Correct Cardbacks for K-Day Datsun Mail-In?

Has anyone had issues with sending in the correct cardbacks for the K-Day Datsun 510 mail-in? I was going through my cardbacks last night to get 20 together to mail off and found that none of them match the “accepted” case codes listed in the rules for the mail-in. Even the ones that I got AT K-Day. For those of you…