I have the same issue. Claimed all the boxes on Thursday 21/11 (time to collect cookies ended on Wed 20/11) and no Grand Prizes for me. Already contact EA Help 2 times. I’ve been waiting a week. I wish I still be able to have those grand prizes.
@7132416515 Please contact our customer support team about this from inside the game tap on settings > help & about > help > contact us.
We fixed this issue in the neighborhood update on November 26, it should no longer occur with the events since that date