Most bogus calls taking one in? Tons! (8)
I believe the answer is:
phoniest
'most bogus' is the definition.
('phony' can be a synonym of 'bogus')
'taking one in? tons' is the wordplay.
'taking' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'in?' becomes 'phones' (I can't justify this - if you can you should give a lot more credence to this answer).
'tons' becomes 't'.
'i' inserted within 'phones' is 'phonies'.
'phonies'+'t'='PHONIEST'
'calls' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Another definition for phoniest that I've seen is " Most bogus or fake".)