@deb24 -- Your iPhone 4 has both WiFi capability and cellular capability. When it is connected to your home WiFi, you can web-surf, and send/receive E-mail, and use Skype & Zoom, even when the top-line on your iPhone shows "No [cellular] Service", but you cannot place/receive telephone calls. Also, if your iPhone is connected via WiFi to the ShawOpen or ShawGo services, you can web-surf, E-mail, and Skype/Zoom, but you still cannot send/receive telephone calls.
Note that Shaw states that Shaw Mobile supports iPhone 5S, and newer, not iPhone 5C, not iPhone 5, not iPhone 4S, and not iPhone 4. A friend activated an iPhone 5C at the kiosk inside the local Walmart, and that iPhone is working fine.