free, what part of Canada are you in?
I had exactly the same problem yesterday. I am in Calgary with Telus.
I was in the middle of a call to BC and the call suddenly ended. I couldn't call back for a couple minutes, managed to get through again, finished the call and then got what you described.
Emergency Calls Only.
I rebooted the phone several times to no avail.
Then it would flip in and out of service, and I got a further message on the screen, with an alert tone every time, something about No data available or similar message. This went on and off at least a couple dozen times.
After a while it cleared up and went back to normal again.
Then a strange one, last night after dinner I noticed my battery was at 53%. Ok, normal. Phone was acting strange so I rebooted it again. When it started back up, the phone got hot and the battery plummeted to 2%. What the ??....
53 to 2% in less than 10 minutes.
By the time I made it to my charger, it hit zero and shut off.
Weird...
Mine is a Samsung S7 - Android. What's yours?