In all fairness, you have to admit that we get much more interesting trolls here than the common-or-garden variety that most forums have to contend with.
Respond to the CEO that you didn't keep a printed copy and your electrinic copy is not recoverable because of a disk crash but that you are certain that it was received because you later received a letter from TIAA acknowledging receipt and following up on it.
In all fairness, you have to admit that we get much more interesting trolls here than the common-or-garden variety that most forums have to contend with.