Yeah it's odd that the tooltip for the Istani License does not say that it contains 15 specific ones (and not the 30 that was available in the first pack). It's also very strange (and very bad) that you can't preview the pack until you already have it in your inventory (from what I saw). They need to change that. You shouldn't be required to look up items on the wiki to get that sort of information.
The
original mount pack is not currently available. They cycle gem store items (during spring and fall iirc) and bring some back for special sales. It will undoubtedly be back "soon". It didn't let you buy a more expensive choosy license tho, just the random and complete collection. Maybe they'll change that when it comes back.
If you didn't use the license you got, you can most probably get a refund.