You can get rid of duplicate contacts by deactivating the setting “Show inactive IDs” (Android) or by activating the setting “Hide Inactive IDs” (iOS) in “Settings > Appearance.” Inactive IDs are IDs that haven’t been used for more than three months. Therefore, it might take a while for contacts to be marked as inactive.
Alternatively, you can navigate to a contact’s detail view, activate “Exclude from auto sync,” delete the contact, and it won’t show up again when performing contact synchronizations (Android).
