On Friday I received a response from NW... it's short and states that when Consumer Service has told you an issue is closed, NW considers it dead & there’s no reason to follow-up on it…

Fine. If a Consumer Service agent suggests I’m a high-maintenance consumer and it’d be mutually beneficial if I took my business elsewhere, then I’ll follow his/her advice. Like I said, I’ve had a string of positive flights with AA… they recently upgraded my status from Gold to Platinum even though I’ve only flown about 16,000 miles with them this year. AA wants my business; NW does not.

More than 10,000 excellent employees of NW have lost their jobs. It’s a shame the Consumer Service agent I initially spoke with wasn’t one of them.