Called Gran, confused (4)
I believe the answer is:
rang
'called' is the definition.
(called on the phone)
'gran confused' is the wordplay.
'confused' indicates anagramming the letters.
'gran' is an anagram of 'RANG'.
(Other definitions for rang that I've seen before include "Made tolling sound or phoned" , "(Of bell) sounded" , "Phoned; reverberated" , "Chimed" , "Called" .)