While possible, if you bought the base game or its expansions, it shows it in the mog station. There is a table with a row of ticks on if you have each expansion or not.



So if you don't see Dawntrail there then most likely the code for it was not registered to your account, or the purchase didn't go through. You can do that via:


As for the "free 30 days" thing, it's worth noting that the "base game" costs roughly the same amount as a 1 month subscription. So effectively, the base game is free and just pays your first subscription fee. However, then it locks you in to paying monthly subscriptions if you want to play, which is of course how they make money from that.

The expansions cost a lot, in contrast, because they see them as a "brand new game". But the latest expansion gives all previous expansions free since all the previous stories are relevant and intertwined with it.

If you got the Complete Edition, this may not be as clear because that is just base game + expansions.