Don’s neighbour has called in disarray (7)
I believe the answer is:
derange
'disarray' is the definition.
(thesaurus)
'don's neighbour has called' is the wordplay.
'don's neighbour' becomes 'dee' (I can't explain this - if you can you should give a lot more credence to this answer).
'has' is an insertion indicator.
'called' becomes 'rang' (called on the phone).
'dee' going around 'rang' is 'DERANGE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for derange that I've seen before include "cause confusion" , "Make mad" , "Drive mad" , "Put into confusion" , "Upset" .)