a case of mistaken identity
An instance in which one is thought or assumed to be someone else. Officer, this is a case of mistaken identity—I can assure you that I did not rob anyone!
case of mistaken identity
the incorrect identification of someone. I am not the criminal you want to arrest. This is a case of mistaken identity.
You must have mistaken me for someone who gives a shit
and YMHMMFSWGAS sent. & comp. abb. What makes you think I care about what you are saying? (Usually objectionable.) So you’re unhappy. Why tell me. You must have mistaken me for someone who gives a shit