iphone se cannot activate cellular data

My daughter's Iphone SE cannot activate cellular data. It says you are not subscribed to a cellular data service. I checked with her service provider and she has plenty of high speed available data. The phone worked fine yesterday but today it does not. She installed the latest IOS a week or more ago. We spent an hour on the phone with cell company trying to get this to work, checking all the settings. She's done a factory reset as well and still not working. Any ideas?