Once activated you should receive a text message confirmation.
If you didn't get instant confirmation it was possibly a pin you purchased for top up that would need to be plugged in on your self-serve account to activate the top-up / tie it to his phone number.
Check on the receipt to see if there was a pin that you can then use.
In future an easier way to get add-ons may be to use the self-service application (https://selfserve.publicmobile.ca/), on the left hand side should be a "purchase add-ons" button, from there it gives you an array of options to select from that will be instantly added to your phone if you have sufficient funds in your account.
