To survive on regular contributions, it's problematic (7)
I believe the answer is:
subsist
'to survive' is the definition.
('subsist' can be a synonym of 'survive')
'regular contributions it's problematic' is the wordplay.
'regular contributions' becomes 'subs' (I can't explain this - if you can you should believe this answer much more).
'problematic' indicates an anagram.
'its' anagrammed gives 'ist'.
'subs'+'ist'='SUBSIST'
'on' is the link.
Can you help me to learn more?
(Other definitions for subsist that I've seen before include "Support oneself at minimal level" , "Eke out a living" , "Get by at minimum level" , "Get by at minimal level" , "Live at a minimal level" .)