how do i block withheld numbers on talk shield

[JBnew]

we have talk shield set up which is great but keep getting withheld numbers getting through.  Can I block all withheld numbers please.

[Mark39]

As there's no number displayed I don't think you can add them to your Block list But you can turn on call screening which results in calls from numbers you've not added to your Star list being intercepted, giving you the option of not taking the call.

[JBnew]

Thanks Mark39

Unfortunately it is for my dad who has dementia and he does not live with me so call screening would not be of any use to us.  Thank you so much for your helpful reply.