I have already bought the soundtrack to the endless legend game before you changed to the deluxe edition, but NOW that you have, it says that I don't own the soundtrack, and that is just bull. I'm frustrated with this even though I have the soundtrack downloaded, this is unacceptable. I own that DLC on steam. It should say on steam that I own it. And they are redirecting me towards you when it's their problem.

I think you've mistaken new lossless Soundtrack that was released only several months ago with lossy MP3s that were included in Emperor Edition of the game from release. You own the latter, not the former.

As Sublustris said. They made another dlc with soundtrack some time ago. The difference is just the quality of files. You still own mp3 version of soundtrack so don't worry.

I'm not sure what you mean by "deluxe edition", since there isn't an item by that name.

You have either the base game (which is "Emperor Edition"), and then you have a bundled pack, which is the "Definitive Edition".

There's DLC available for the base game which includes the items in the Definitive Edition. Beyond that, it includes items that the Definitive Edition does not include, which are the free items and the OST. The OST is separate from the Definitive Edition that includes an album DLC. You wouldn't have any of the items revoked without notification. If you're thinking Steam pulled a fast one on you, take careful review at the fact they're two separate packs:

https://store.steampowered.com/app/1275460/Endless_Legend_Original_Soundtrack/
https://store.steampowered.com/app/415700/Endless_Legend__Echoes_of_Auriga/