"The FDA letter is not simply citing a manufacturing deficit or a benign mistake. "
Maybe you should re-read as it is a WARNING letter, and it was due to products being mislabeled. Corrective actions were taken before any legal actions were taken unless you have proof where legal action was taken against ABCO, not a WARNING letter.
"You should take prompt action to correct the violations cited in this letter. Failure to promptly correct these violations may result in legal action without further notice including, without limitation, seizure and injunction. "