So it sounds like there was some kind of usage.  

You need to login to your self serve and download your detailed PDF ebill and I recommend reading and following the article in the link below to determine the exact cause of the usage for each of the days the pdf ebill says roaming was charged.

Let us know what was the usage that was the trigger for roaming charges for each day

So I did all below, there was little usage on one or 2 days, but some days no usage of data, only messages received and no calls and I still got chagred, one excample is nov 27. Only call that shows incoming is from my own number( not sure why). Many other days that were charged are also with 0 data 0 calls etc, probably only 3 of the 10 days I was charged I actually used any data

You mention days charged for Easy Roam with no Calls and Data used.  Have you checked if there were texts sent?

For Nov.24 & 27 I see calling which was what triggered the easy roam (note that when your own number is noted for an incoming call, it typically means there was no Caller ID available).

For Nov26 I would check for text messages

I see Data usage for Nov.24, 25, 28, 29, 30 and Dec.1, which aligns with why you were charged for Easy roam on those days (except for Nov.28 you used data but did get charged for Easy roam - Were you in the US from Nov.24-Dec1?  Or were you back and forth in Canada and the US?)

I was in the US those days nov 18- dec 1 all through.. there were no text messages on those days only incoming I dont use text messages, the call I got from my own number was 0 minutes and seconds

Like I said even the data looks weird as I was using this only as my secondary sim card.

Clearly data was used.

Did you set the US sim to only use Data (turning your Koodo sim data off completely)?  From the looks of it, it looks like Koodo was used as secondary data when your US sim was not working or had a slow connection.  Or maybe the US sim had a data cap that was exceeded which is why we see Koodo data usage only on the end of your trip and not the beginning.

Koodo will not reverse the roaming when data was clearly used.

If you want, I can flag a rep for you.  But from what I see in your screenshots, you should have been charged Easy roam for Nov.28, but you were not.  The assumption is Nov.26 it was texting that triggered the roaming but you have not posted a screenshot to show otherwise.  The 2 dates cancel each other out.

Worse case scenario, the Nov 26 usage is confirmed by Koodo, and they correct the billing error and charge you for Nov.28 as well.

Did you still want me to flag a rep?

I had data roam off, but how can I prove that? I guess its no use

If you had data roaming off, then there would be no recorded usage.

Either the setting was turned off wrong or the setting reset itself (this can happen for certain phones like when you restart your device).