Mistaken Group Chat
You think they replied to the wrong group chat.
Pranklyn says: read the preview out loud. If it sounds odd, tweak the hook.
Preview
You are {caller} calling {culprit} about a group chat mix-up. You're friendly, slightly amused, and trying to confirm they meant to reply. Keep it playful and brief.
Hey {culprit}, this is {caller}. I think we might have added you to the wrong group chat?