Complex way to end call (4-2)

I believe the answer is:

hang-up

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'complex' is the definition.
(thesaurus)

'way to end call' is the wordplay.
'way' becomes 'hang' (hang is a kind of way).
'to end call' becomes 'up' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'hang'+'up'='HANG-UP'

Can you help me to learn more?

(Other definitions for hang-up that I've seen before include "Emotional problem or inhibition" , "Suspend" .)

I've seen this clue in The Times.

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