Hi Gil,
For us to better understand this issue, how did you add these contacts? are they manually added or did you add them by connecting your 3rd party accounts to the account posted above?
If you added your contacts by connecting it to your 3rd party account, please be informed that you can't delete them. To be able to delete a duplicate contact from your 3rd party account, you have to delete it on your 3rd party account (i.e facebook.com, twitter.com, etc.).
We're looking forward for your response so that we can further assist you.
Thank you.