I had the same thing happen. My actual AP said expires Dec 1, 2014 but MDE said it expired in Sept. After multiple emails and phone calls, I had to go in person to guest services to have it fixed. Then, the very very snotty CM said the ticket agent must have written the wrong date on the AP!! I was like, "um....no! I wasn't even at Disney in September. I used my ticket on Dec 1 AND upgraded on Dec 1!" Anyway, she finally changed it on the computer but it was an unpleasant experience!
Wow! I should have receipt from my credit card that I charged the upgrade on. Hopefully I can do it over the phone or I can't schedule any FP for our visit in advance (not that I really am that thrilled about having to schedule in advance anyway)... But this definitely explains what happened and will hopefully make it easier for me when trying to explain it over the phone! Thank you everyone!!