That's a curious case. I looked up the status of the inbound flight (KL1505) that brings the plane to NWI.

On flightstats.com that flight is still shown as scheduled with no further information.
On schiphol.nl that flight is also shown as scheduled with no further information.
On klm.com that flight is shown as "arrived" with a delay of 82 minutes (10:27 instead of 09:05).

Do you know if that plane actually arrived?

Looking at flightstats.com for NWI departures in the morning period I see that a flight at 8:45 was 40 minutes late, the next flight after your cancelled one was at 11:45 and on time.

I assume that the earliest possible departure of your flight would have been in the 11:15 area.

Did you actually fly to AMS today? If so, was it on the later flight at 17:15?

Edit: Some more findings:
- The flight is not found on flightradar24.com
- Similarly no data was found on libhomeradar.org
- Even on schiphol.dutchplanespotters.nl the flight shows "expected" as its status. (Edit 2: This is because the website gets the data from schiphol.nl)
- The early NWI-AMS flight arrived at AMS almost 2 hours late

I get a gut feeling that the KL1505 never really left AMS today.