I had the Forsaken expansion, but as far as I understand I lost it... Really sad that bungie/steam weren't able to take all the database from battle.net. Isn't any other way to just have back an access to the game? If not I'm not sure I'll buy the game one more time...
You had to manually move the licence as Bungie has no access to your accounts. The game is free to download and play but your licences and characters are now lost I'm afraid.