I need bill to be adjusted, but it's fixed (9)
I believe the answer is:
indelible
'it's fixed' is the definition.
(thesaurus)
'i need bill to be adjusted' is the wordplay.
'to be adjusted' indicates anagramming the letters.
'need'+'bill'='needbill'
'needbill' anagrammed gives 'ndelible'.
'i'+'ndelible'='INDELIBLE'
'but' is the link.
(Other definitions for indelible that I've seen before include "Of mark or stain, unable to be rubbed out" , "Of stain, unable to be removed" , "fast" , "Cannot be removed or erased" , "Permanent" .)