Following instructions, debit one at random (8)
I believe the answer is:
obedient
'following instructions' is the definition.
(I've seen this before)
'debit one at random' is the wordplay.
'at random' is an anagram indicator.
'debit'+'one'='debitone'
'debitone' is an anagram of 'OBEDIENT'.
(Other definitions for obedient that I've seen before include "Ready to agree" , "Docile" , "Submissive, compliant" , "A good dog should be" , "Ready to comply" .)