Rang - that's the whole point - did ring (7)
I believe the answer is:
dialled
'rang' is the definition.
'the whole point did ring' is the wordplay.
I cannot quite understand how this works, but
'whole' could be 'all' (I have seen 'The whole ' mean 'all' so perhaps 'whole' could also mean 'all') and 'all' is present in the answer.
'point' could be 'e' (compass point) and 'e' is present in the answer.
The remaining letters 'did' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'that's' is the link.
Can you help me to learn more?
(Other definitions for dialled that I've seen before include "Rang (a number)" , "Telephoned" .)