Happy maybe to receive information initially not delivered? (6)

I believe the answer is:

unsaid

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'not delivered?' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for unsaid that I've seen before include "Tacit" , "withdrawn" , "left to the imagination" , "not delivered" , "Not uttered" .)

I've seen this clue in The Independent.

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