I just returned from Ecuador and had data turned off the entire length of the trip (although not in airplane mode, just data toggled to off.). Upon landing at the airport I turned my data back on only to see that my phone said there was no service in my area, followed by asking if I would like to place my phone in roaming mode. I tried changing the network preferences but if im honest I don't really know too much about all of that. However, in the days to come I was able to connect to 4g LTE only mode but could not make or receive phone calls, I can only use data and send texts. I've looked around for a thread with a similar problem but have found nothing. I have tried restarting the phone and removing the sim card but neither have worked. Any help is much appreciated. Thanks. I have a HTC One (M8)