Well I never pay for rubbish! (2,4)
I believe the answer is:
my foot
'rubbish' is the definition.
(phrase used to dismiss something as rubbish)
'well i never pay' is the wordplay.
I cannot really understand how this works, but
'well' could be 'my' (both are expressions of surprise) and 'my' is found in the answer.
'pay' could be 'foot' (as in footing the bill) and 'foot' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for my foot that I've seen before include "Definitely not" , "Nonsense!" , "bunk!" , "rubbish!" , "I just don't believe it!" .)