Old Soundtrack

What do I need to do to get the old soundtrack back?
I don't want to even play the game because of this.
It's like an actual betrayal league happened and now I don't understand.
Why can't we just be given the option to switch? Why would you take away all of the nostalgia? I want to play the game but it's just too hard knowing the atmospheric music I love is completely erased from the game, and for some unknown reason.

There's nothing unknown about it and there is a reason.

Because GGG does not own the rights to the material and the composer no longer works for GGG.