The correct spelling of the phrase "wast given one due" is "was given one's due." The "t" in "wast" is archaic and no longer used in modern English. The correct pronunciation of the word "due" is /duː/, with a long "u" sound. The "e" at the end of the word is silent, but it is necessary to indicate the pronunciation of the vowel before it. "Was given one's due" means receiving what one deserves or is entitled to.