Comes up against a bill and what goes on it (7)
I believe the answer is:
accosts
'comes' is the definition.
(accosting is a kind of coming)
'goes on it' is the wordplay.
'goes' becomes 'acts' (I've seen this before).
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'it' becomes 'cos' (I can't justify this - if you can you should believe this answer much more).
'acts' going around 'cos' is 'ACCOSTS'.
'up against a bill and what' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for accosts that I've seen before include "Grabs" , "As a solicitor does" , "Approaches boldly, solicits" .)