Return but don't exactly repay (5)

I believe the answer is:

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'repay' is the definition.
(I know that repay is a more specific form of the action reply)

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for reply that I've seen before include "response is demanded" , "Comeback" , "Reciprocate" , "Answer, respond" , "acknowledgement" .)

I've seen this clue in the Evening Standard.

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