I would first turn off the phone, wait 20 seconds then turn it back on. then set the phone to airplane mode, wait 10 seconds then switch it off airplane mode. If you can’t receive calls from certain numbers, check to see if you accidentally blocked them in settings > phone > blocked contacts. Next see if call forwarding is turned on. Go to settings > phone > call forwarding and make sure it's off. Next check to see if silence unknown callers is turned on. If the setting is on, a caller must be listed in your contacts or recents. Or they must have shared their number in mail or sent you a message using that number in order for their call to go through. Add their number to contacts to ensure the phone rings. Calls from some third-party apps might not go through.
I would also make sure your phone’s operating system’s up to date. If that doesn’t fix it, you can remove your SIM then reinsert it. The only outages I see are in Vancouver Island so unless you live there you should be fine.
