To prevent this in the future, please change your network settings from Automatic to Manual and then select Koodo.  This will prevent your phone from connecting to a roaming network.  Note that you may have to redo this after you restart your phone.

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

I have also flagged a rep to look into your accidental roaming

Hi ​@Bethp, please note charges can generally be disputed in the 30 days following a bill being issued. We’ve made an exception and checked the charges you mentioned and as they are accidental roaming we have added a credit to your account, you can check it out in your self-serve.

To avoid future charges please make sure that the data roaming is off in your phone settings and you are manually connecting to the Koodo network.

For more information on how to prevent accidental roaming charges, please check out this article https://community.koodomobile.com/plans-services-232910/easy-roam-understanding-how-you-will-be-charged-while-traveling-7811296