When you said you didn’t use, did you take the Koodo SIM out of the phone? or  disable it? did you receive any roaming SMS from Koodo?

Additionally, I recommend you check your usage in self-serve to see why Koodo charge you for roaming.

We had the phones with us but made no calls, no text and no data use. As per the notification when we crossed into the states it said as long as we used none of the above we would not be charged.

I should not have to pull my Sim card or disable my phone. I received no calls or text during the 3 hours we were in the states.

Did you turn off “data roaming” and cellular data during that time, the phone can access data on its own, and that could trigger roaming fee.

As I mentioned earlier, Please check selfserve » Usage of data/text/call to see which service Koodo claimed you used.