I among other users have lost legacy booster packs from the store/vault. The booster packs lost are the faulty legacy booster packs that we have gotten over the last (few??) months. It is the packs that had fewer cards in them. They were missing some sets common and uncommon cards.
I’m glad you were able to get a resolution… eventually.
I’m disappointed that the management team at Webcore didn’t anticipate the existence of bugs after a new release and, because of this oversight, failed to adequately staff their customer support department resulting in such a long delay responding to tickets.
I also found these boosters missing a little while ago and seem to have had them restored today (I think… I have a lot of boosters in my Vault so it’s a bit hard to keep track of them ^_^)
Here’s the older thread relating to the boosters which had fewer cards in them that OP was talking about
Reading the message from support again, it seems that the solution the devs had to make took time because it was a solution that covered every afflicted player.