i hate my new phone

How did you get the phone? Technically you could return the phone if your device was still in perfect condition within 15 days (30 days for online purchase). More here https://www.koodomobile.com/en/help/returning-or-exchanging-your-koodo-phone

Also, which phone model was it? And how did you get it?

If you purchased the iPhone in-store, you have 15 days from the date of purchase to return it and either  exchange it for a different phone, or get a full refund. If you ordered the iPhone online, you have 30 days from the date of purchase to return it. Online purchases must be returned via mail and can be initiated by sending Koodo an email to koodo.webstore@koodomobile.com.

Note: there's no exchange process online, which means that, if you're not satisfied with the phone you received, you must return it and buy another phone. Please note that a shipping fee will be applied to the new phone.

Returning or exchanging your Koodo phone

Thank you for the answers! I’ve emailed them to start the return process. I purchased through the online store and it’s an iPhone 11 Pro, still in perfect condition of course as I just got it a few days back

You're good to go then to return it. Don't worry if it takes s a few days for them to reply. You reached out within the time window and you're good. If there's something major you're having issues with, you can ask us. At least you can have a less unpleasant experience until you return it. Or if you still have your old phone you can just use it in the meanwhile.