Hello @Ilandr_99
It's super easy to do. Log into your account, use this direct link to change your card.
https://myaccount.publicmobile.ca/en/account/payment/manage-card
If you run into problems, the Public Mobile website is known for cache issues. Simply go into your browser settings, find the cache and clear the history of it. You may need to clear cookies as well. The close the entire browser, restart it and go into incognito or safe mode and try again.
You can also use the app which I find the easiest as well.
