Complaint about individual having left the building (4,3)
I believe the answer is:
gone out
'left the building' is the definition.
(not at home)
'complaint about individual' is the wordplay.
'complaint' becomes 'gout' (gout is a kind of health problem).
'about' indicates putting letters inside.
'individual' becomes 'one' (an individual is one person).
'gout' placed around 'one' is 'GONE OUT'.
'having' is the link.
(Other definitions for gone out that I've seen before include "On The Town possibly" , "Having left the house (to go to a party?)" , "dated" .)