mistaken identity, mistaking someone for another person
人違いだろ
You've got the wrong person.
— 自転車泥棒 (1948)
調べてみたら人違いだった。
I looked into it, and it turned out I had the wrong person.
受付で人違いされた
They mistook me for someone else at the reception desk.
— 嵐の中で (2018)
人違いよ
You've mistaken me for someone else.
— エリート・スクワッド (2007)