Phone doesn't work in france

I have premium unlimited plan. I arrived in France 10 hours ago .  phone will not make phone calls or send texts.  phone will not connect to XFINITY SIM data, even though it's on roaming .  Will only connect when on Wi-Fi.  I've turned the phone off and on numerous times and have left it off for about 10 minutes .  I tried contacting customer service three times.