You are correct. The SIM card number is in the system, by going forward the system thinks you’re trying to activate the same SIM card number and returns with ‘invalid SIM’. I think your best option is to send a private message to Koodo via Facebook to have your prepaid account reset. 

https://www.facebook.com/Koodo

I’ll give this a shot, thanks!

When activating on prepaid, it’s strongly recommended to have everything lined up so that you don’t have to interrupt or backtrack. Have your credit card, correct billing address from a statement and SIM  number writ large and ready to enter correctly without fumbling to read the tiny number.

Choosing a baseplan or booster: it’s a better idea to top up your account first, and use the balance to fund the purchase. It can be confusing otherwise when the system bounces you back and forth to the payment screen. You might think that you actually bought something, but ended up just added money to your account.

When you’ve finished your transaction, re-visit your summary page to make sure everything has posted correctly.

Hi there! Happy holidays! For more info about activating your sim card, please visit this link https://koo.do/3hknxZL or schedule a callback at your convenience at koodo.com/chat. 

On the “Getting Started” page and perhaps in the “Activating your prepaid phone” page, there should be a cautionary note advising prepaid customers not to use the “back” button when filling out prepaid activation forms. There’s plenty of opportunity to change or transfer an existing phone number once the customer’s prepaid self-serve portal is up and running.

I understand that this circumstance does not happen very often, but I think this would have saved the customer time and Koodo’s resources could be put to better use. Just a thought.