To pay by phone you need to call 611 from your koodo number. Unfortunately if you left koodo this won't work. 

I would recommend paying via online banking.

You can also try clearing your browser's cache or try a different or device

I think your best option is to send a private message to Koodo via Facebook Messenger or a DM via Twitter. I don’t believe dialing #227 will work since you are no longer a Koodo customer. You’re welcome to try it though.

https://www.facebook.com/Koodo or https://twitter.com/koodo 

@BillieBob You have access to the online services of your account 90 days after cancelling a line. We can see attempts to pay the bill however it appears there is something up with the credit card as payment is not going through. Pls contact the financial institution that issued the card and they should be able to assist with a fix.