The DLC content you bought is still there and can be played just fine. You're also missing the fact that MMO worlds NEVER freeze in time. The only thing thats frozen is quests designed to tell the story as a progression. The end game world moves forward continuously. Same thing happens in every other mmorpg. Thats also why you cant get the grimoire from HoW finished completely. The fallen public events are over, a new enemy has arrived.