Duplicate contacts in Sync.ME are due to c ontacts brought from other sources in the address book, such as iOS Facebook integration, contact exchanges, etc.
iOS automatic Facebook integration can cause duplicate contacts. This is unrelated to Sync.ME, and can be disabled by going into your device settings: Settings->Facebook->Contacts . Turn this Off to disable.
If you are also using a separate contact exchange (such as Google Sync, Outlook, etc.), you may see multiple contacts listed for the same person. In order to minimize these issues, we recommend to store your contacts locally by using CardDAV, instead of your normal contact exchange. To sync your Google contacts with CardDAV, click here .
>>You can also upgrade to the Premium Pack and use our Contact Merge feature to merge duplicate contacts. Below is more info about this new feature:
About Contact Merge
How to Merge My Contacts