I am a "Platinum Medallion" member at Delta. I purchased some SkyMiles by mistake and Delta now says there is no way possible for me to cancel the transaction under any circumstances whatsoever.
Trying to resolve the issue with Customer "Service" was a complete waste of time. According to a post by one of their customer service reps on the Delta blog about reversing initial decisions made by their reps, "Unless we made a mistake on the initial review of your complaint the decision in most cases stands." (http://blog.delta.com/2008/05/19/ten-tips-for-resolving-a-travel-complaint/)
Perfect description of how to stick to your principles, never give in....and lose customers.
So, I'll start traveling on other carriers now. Funny that they would give up $50k-$60k/year for my lousy $300 bucks but hey, if they want to lose $200 for every $1 of mine that they keep, I can see why they filed for bankruptcy.