Not enough decorations?

So I've just come back to the game after close to a year away and was stoked for the Christmas events, I've been hammering away at the missions to get the boxes for decorations and my decorations level is at 9 with 2 ornaments still needing to be level 5. The issue I see is with the missions I can only earn 6 more boxes.. which may not be enough to hit level 10 and absolutely will not be enough to finish off a collection. My question is, is there something I'm missing? Is there other ways to earn shards or decorations? and I'm aware of the decoder and how it works, I've just had terrible luck with it so far.