get your wires crossed
US /ɡɛt jʊər waɪərz krɔst/
UK /ɡɛt jʊər waɪərz krɔst/

1.
se mélanger les pinceaux, se croiser les fils
to misunderstand someone or something, especially in communication
:
•
I think we got our wires crossed because I thought you were coming tomorrow, not today.
Je pense que nous nous sommes mélangé les pinceaux parce que je pensais que tu venais demain, pas aujourd'hui.
•
It seems like we've got our wires crossed about the meeting time.
Il semble que nous ayons mélangé les pinceaux concernant l'heure de la réunion.