How would I say the phrase "Retaliate with Success" in classical Latin?
Prospere seems a good word for 'with success'. For an example, I immediately thought of 'prospere, procede, et regna' from the Psalms (though granted, that's ecclesiastical.
For retalitate, I rescind my previous answer of punire - instead I propose ulcisci, which my Lewis and Short marks as common in classical usage, as in “odi hominem et odero: utinam ulcisci possem! sed illum ulciscentur mores sui,” Cic. Att. 9, 12, 2.
Thus, I have Prospere Ulciscimini or Prospere Ulciscere, depending on the number.