I have an iPhone with Whatsapp, and a Windows PC with Outlook 2016 that also runs iCloud sync, to sync Outlook contacts with iCloud.
Somehow, phone numbers from one contact have been copied over to other contacts with similar names (not necessarily the same name, just similar). I'm not sure how many contacts have been affected, or even if it's just the phone number field.
I would assume iCloud sync, Outlook or Whatsapp has screwed this up, I'm not sure which.
My idea is to compare phone numbers within an exported vCard or CSV file, and see which match. Hopefully there aren't too many and can be corrected manually.
I need suggestions for a vCard or CSV comparison program or any other ideas for sorting this out.