At subsistence level, phoning to secure money (2,3,9)
I believe the answer is:
on the breadline
'at subsistence level' is the definition.
(I've seen this before)
'phoning to secure money' is the wordplay.
'phoning' becomes 'ontheline'.
'to secure' indicates putting letters inside.
'money' becomes 'bread' (bread is a kind of money).
'ontheline' enclosing 'bread' is 'ON THE BREADLINE'.
(Other definitions for on the breadline that I've seen before include "impoverished" , "with barely enough to live on" , "Phoning to secure money" , "Poor" , "Barely getting by" .)