Unfortunately, Once you cancel (which is what happens when you port your number out), the prepaid account is closed and all boosters and topups are forfeited.  Topups and boosters are not refundable.

https://www.koodomobile.com/en/help/topping-your-prepaid-account

Ideally, it is recommended that you should use all your boosters and topups prior to transferring out

How can Koodo forfeit my money? Is it legal? I still have over 100$ in my pre-paid account.

This is why it is recommended to use all your funds prior to canceling your Koodo prepaid account since top-ups are non-refundable

Is there any condition indicating that the top-ups are non-refundable?

Yes, it’s mentioned in the service terms.

”Prepaid service credits are non-refundable and are not reimbursed if service is cancelled.”

https://www.koodomobile.com/en/service-terms

Thanks Allan, however, the “ prepaid service credits” means the top-ups? I topped up the money in my account, but didn’t use it to buy add-ons or other service.

Yea, service credits are the unused topups in your account. It says in the same paragraph “You can get service by using your prepaid service credits to purchase a base plan.”, which confirms it.

It also mentions that unused boosters and days left remaining are forfeited further down in the paragraph as well.

Yes they do.  Since top-ups are the only way you can purchase a baseplan.  So Top-ups = Prepaid Service Credits