I hope you saved the body and took it right back to the LFS, or are planning to do so . . . they should never have charged to for that fish (it should not even have been for sale), but they sure as hell ought to give you your money back
either way, let them know that it was not acceptable to have sold it to you, and if they give you a hard time, let them know you'll never shop their again (you probably shouldn't shop their again anyway)