I have flagged a rep for you as well

To prevent this in the future you can change your network settings from Automatic to Manual and then select Koodo 

https://community.koodomobile.com/plans-services-232910/easy-roam-understanding-how-you-will-be-charged-while-traveling-7811296

Hello @sydneytav 

Sometimes the device is going to catch the network on the other side.

It's a world-wide situation, since the device settings are set to automatically search for the strongest signal.

You can change that in the settings of the device and set it to Manual Network Selection, after it's done searching, you select Koodo and it stays connected to Koodo, even near the border.

I would also advise to keep Data Roaming off while in Canada. This will avoid any accidental charges. We have a great help page here: https://community.koodomobile.com/plans-services-232910/easy-roam-understanding-how-you-will-be-charged-while-traveling-7811296

We verified the day with the charge and confirmed accidental roaming. A credit was applied for the fee and will update within 3-5 minutes in the Self Serve account.