May I ask for some advice from experienced flyers regarding an award ticket. . .
I just returned from a European trip and was able to get a low tier award with a crazy return routing that had me land in MSP and then use two additional segments a week later to get home. But I live close to MSP, so I just landed there today and took a bus home.

I now have two unused segments in F that I will not be using, scheduled for next week. I just went to to the DL web site to cancel them, but I got an error message that I can't do that once a trip has started.

Those of you with experience: should I call DL by phone to cancel or just no show for those segments? In any event, I am not entitled to any mileage refund but don't want to get a change fee. Any repercussions in my future?

I know I scammed the system, but ease my conscience knowing it is a screwed up system.