Do you want to restrict international calls made from your phone?
In this post, it looks like Xfinity customer service can apply restriction to a home's phone number. Possibly same restriction can be applied to a cellular phone number/account?
Hope this helps.
thank you for your response. home phone department does not have way to restrict Xfinity mobile.
but they gave xfinity mobile international service phone number : 720-728-5462
and they were able to bock it
Great you got it working. Thank you for updating your post with resolution.