Daughters contacts have appeared mixed in my contacta

How do I remove my daughters contact from my contact list? They just appeared in my contact list earlier today and have changed all the names in my call log, messages, emails and WhatsApp. If I delete them from my phone it removes them from hers so I can’t just do that. We have separate Apple IDs and use family sharing. Nothing has been changed and is the same set up that’s been fine for the last 3 or 4 years until today