it is reiterated throughout the movie, at least twice from what I can remember, that all of the children are fine and are simply sent back to their homes with no reward, but they'll be "a little wiser"
sweety:) check you facts before you come at me. it says right here in the script:
"Charlie: Mr. Wonka, what happened to Augustus?!
(Willy Wonka smirks, the first trace of bloodlust glimmering in his eyes)
Wonka: He's dead, Charlie. He's loving dead."