If you are reading this, then you are aware of the recent problem that EU Hearthstone players have been facing, such as missing adventure and cards. And you might even be one of the frustrated players that experienced this mishap. So in the light of this unfortunate situation, Blizzard has announced that they have fixed the issue. But if you still experience this problem, we recommend that you reset your Battle.net account passwords since Blizzard suggested that it can resolve the issue. If this does not work, then Blizzard has offered their support team to address the issue for you, and you can reach them by clicking here.
Blizzard should be able to fix the issue once and for all after you have contacted them. Another solution has come up that Blizzard has posted as well. Launch the game and see if you find custom decks with a red X visible on top of them. If that is the case, then it’s best to edit the affected deck, remove any card from them, and save the deck. Following that, return into the deck, add the removed card back, and try to save the deck. This procedure should fix it for you.