Backing provided while company reveals complete disaster (6)
I believe the answer is:
fiasco
'complete disaster' is the definition.
(I've seen this before)
'backing provided while company' is the wordplay.
'backing' shows that the letters should be reversed in order.
'provided' becomes 'if' (eg 'provided it's sunny' means 'if it's sunny').
'while' becomes 'as' (eg 'while I walked' means 'as I walked').
'company' becomes 'co' (abbreviation).
'if' written backwards gives 'fi'.
'fi'+'as'+'co'='FIASCO'
'reveals' is the link.
(Other definitions for fiasco that I've seen before include "Embarrassing failure" , "Complete and utter failure" , "Farcical disaster" , "A ludicrous failure, a shambles" , "Ignominious failure" .)