Called in, dear, to straighten out and it’s fixed (8)
I believe the answer is:
arranged
'it's fixed' is the definition.
(I've seen this before)
'called in dear' is the wordplay.
'called' becomes 'rang' ('ring' can be a synonym of 'call').
'in' is an insertion indicator.
'dear' becomes 'ared' (I am not sure about this - if you are sure you should believe this answer much more).
'rang' put inside 'ared' is 'ARRANGED'.
'to straighten out and' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for arranged that I've seen before include "Scored" , "Ordered" , "Organised, planned" , "Fixed" , "Settled plans for something" .)