Well it is a shame that they did not go with your work for it is far superior then the very basic Anime looking face they did get. But you still have this really amazing piece of work to share with all of us!
Lindsey Stirling is starting to develop a reputation for either shitting on those who helped her in the past, or not giving a shit about anyone other than herself anymore. I used to really like her stuff, but I have unfollowed her on everything as her attitude continues to decline and I see more and more reports about how she is as a person. I am sorry that you got caught in her bullshit. This is an absolutely beautiful piece.
There are many ways to do it, I think it depends on the part of the industry you are, I guess. Some pay half up-front, or half after some work is done, or full in advance...
But even if they end up not using your work they should pay something. You did the work, I assume they approved it along the way, if they change their mind that is their problem. I don't know, that is my opinion.
I just googled that album and wowww I can't believe they chose the most basic anime face over your art?? Are they for real??
But anyway, great job on your end, I really like the color harmony.
in the end a VERY anime look is what they go for. Ive learned that for the most part the actual look is much b etter than the album cover they went with. This was for the accompanying comics.