refferalscode

Too late
You can try to ask the support, but it is too late

here the text from the guide

If a person forgets to enter the referral code when subscribing, they’re unfortunately out of luck. We cannot retroactively apply a referral code.

Source: https://fizz.ca/en/faq/how-do-i-invite-friends-to-join-fizz

You can contact Fizz support by chat, from 8 AM to 9 PM everyday:
1- Connect to your Fizz account by clicking « Login » in the top right corner at fizz.ca
2- Click on this link: https://fizz.ca/en/faq/how-do-i-invite-friends-to-join-fizz
3- The green chat bubble should appear after a few seconds in the bottom right corner.