@Barbra - sometimes toggling into airplane mode in the settings of your device, then going back to regular mode can help connect to the network.
If you are still having issues after suggestions already provided, can you try your SIM card into another phone to see if services work?
If so, install your SIM back into your phone; that may have triggered a network refresh just doing that action of swapping the SIM cards.
And, just to be sure check that your phone is not blacklisted here: https://www.devicecheck.ca/check-status-device-canada/
