I updated my phone last night, and now I'm unable to make calls. I'll show 3 bars of service, but as soon as I dial out, it drops to zero and says Mobile Network Unavailable. I'm not sure if it's a phone or area issue (weather here is fine) and I haven't been able to talk to anyone on live chat today.
Have you tried reseating your SIM card? Turn off the phone, remove the SIM card, wait a minute or so, then reinsert the SIM card, turn the phone back on, and allow time for a fresh network connection to be established. Also ensure that your network setting is LTE/CDMA and not Global.