Dee called in to cause confusion (7)
I believe the answer is:
derange
'cause confusion' is the definition.
(I've seen this before)
'dee called in' is the wordplay.
'called' becomes 'rang' (called on the phone).
'in' is an insertion indicator.
'dee' enclosing 'rang' is 'DERANGE'.
'to' is the link.
(Other definitions for derange that I've seen before include "Put into confusion" , "Make insane" , "Craze" , "Unhinge" , "Drive mad" .)