If you are receiving unwanted calls in Skype, you can change your call settings to only allow calls from your contacts to ring on your device:
- Select your profile picture.
- Select Settings.
- Select Calling.
- Toggle Only allow calls from contacts to ring on this device to On.
If someone who isn't in your contact list calls you, Skype will show a missed call from them.
Changing this setting does not apply to incoming voice messages, or calls to your Skype Number. Anyone can still leave you a voice message, or call you on your Skype Number.