Did you actually purchase the proper 10 day package? The $40 US Roaming package is the one that includes data. If you bought a 10 day one that was less than $40, then you purchased one without data and were thus incurring pay-per-use charges on data.
That or you went over the 250MB alotment which you bill should tell you how much data was used while you were roaming
What phone do you have? If I recall, 1x data was a CDMA form of data, not the form used for GSM phones. EVDO (1x) data makes little sense if you are using a current smart phone, as it was used on the old flip phones (the ones without SIM cards) of about a decade ago.
I suggest contacting Koodo directly to find out more.