Misleading product advertising, testing showed it was mostly (non kinder) Oompa-Loompa meat, it was a whole thing, they settled out of court.
At the time Wonka blamed it on management board, fired them, & replaced them with random ppl chosen by chocolate-raffle method, but later some emails surfaced that showed managers basically had no choice in the matter.
All he needs to do for good public relations is a lame contest with, let's say, a golden ticket to his factory and nobody asks questions about missing children or Oompa-Loompas anymore.