Have you tried taking the uneaten food back to the pet store??
I don't know what other stores policies are... But I used to work at a local pet store, and we'd take food back if your dog didn't like it or got sick from it or something. You just needed the original packaging, the leftover food and your original receipt. We would give a store credit for it which you could use to try another brand.
Good luck. I'm fortunate that Pixie will eat whatever I put in front of her....
Edited: I just saw Lucky's Mom suggested the same thing (Great Minds Think Alike, right?
) We would take back any brand, not just SD. Try calling the pet store, it's worth a shot!