Roaming Charges to dispute

To avoid this in the future since you live close to the border, i suggest changing your network settings from Automatic to Manual and then select Koodo.  Note that you may need to reapply this setting change after a phone restart.

I will also flag a rep for you to see about your charges.  Please make sure you are logged into the community with your self serve account.

Hello ​@Senior me  

A bill can be disputed within 30 days of the released date. Roaming charges can have a delay and appear on a later invoice, so we check the past 90 days for this specific charge. We have reviewed the last 3 invoices and we found roaming charges only on your latest released invoice. We have been able to remove the roaming charge since it was triggered due to accidental data roaming, feel free to check the details in your self serve account when you get the chance.

For more info about how to prevent accidental roaming charges, please check out the link shared by ​@Dennis 

Also, feel free to check the available  plans in your self serve account, as you might be eligible for a Canada-US plan: https://www.koodomobile.com/en/help/changing-your-rate-plan

With a Canada-US plan, there will be no fees for when the phone picks a US tower while near the border,. On top of that, you can use your phone without additional charges in US (some exceptions apply). More about Canada-US plans, you can find here https://www.koodomobile.com/en/help/traveling-with-your-canada-us-rate-plan