In order to reject calls from people who are not SkyPrivate members, you need to log into your SkyPrivate account and in:
Settings ⇒ Public Profile ⇒ Plugin Settings, select "Yes" at "Reject calls from users not on SkyPrivate".
This setting will still allow persons to add you on Skype, but the ones who are not SkyPrivate Members will have their calls rejected instantly by the plugin.
We strongly recommend to our Models to activate this feature!