Wifi calling, as mentioned, is no cost to the USA and no cost for callers to you from the USA. If I called the Peli Deli from SBR it would be an international call. If I call California from SBR there would be no charge

I have received (in SXM) maybe 5 calls from contacts in the USA this week...no issues EXCEPT you will not have access to voicemail. It will show a missed call and you can call them back