I've been stuck on the Christmas quest since it ended last month. There's a quest reliant on a character I don't have and I've tried clearing the cache, restarting the game, restarting my phone, uninstalling and reinstalling the app, even tried to contact the EA Help Center but they keep suggesting the same fixes I already described then the chat times out and a new person suggests the same things I already tried and I have to start over with their support team.