Fortunately, the account is already closed if porting has begun and you need not worry.
UNLESS... if your Public Mobile renewal was set to occur within a day or so of the date you ported out, there's a small chance the renewal may charge to your payment card.
Keep an eye on the payment card transactions and contact the Customer Support
Agents should that occur - they'll reverse it for you.
Sorry to see you go!!!
As stated use the IMEI to port your number to koodo. If you dont know the 4 digit account pin # via 611 you can always play it safe after porting out by putting your autopay card on hold overnight from midnight eastern to noon eastern on your renewal date to absolutely ensure no payment is charged to your card.