Same thing happened to me the other night. Chef Mickey reservation disappeared. I closed out of the website and rebooted my computer. It was back. I think it's a glitch in their system.
1) Maybe.
2) However, after handling complaints from MANY, MANY guests, we can usually trace it back to an error by the guest.
. . . sometimes they cancel the wrong ressie
. . . sometimes they make a ressie at the wrong eatery
. . . sometimes they forget to SAVE the ressie properly and it doesn't get made
3) If you have your Confirmation, you can call the ressie department and they can usually trace down the problem and get it corrected.
4) This is why we always tell folks to print out their confirmations hotel-food-FP, etc.