Here's your solution: ditch DL
This is exactly why I jumped ship from DL as a GM years ago: not only devaluation of SM FF benefits, but this overall customer-unfriendliness and poor attitude.
Since you were flying from PHL, why not use US? I guarantee you that your experience with US would have been exponentially better. I'm now a very happy CP with them, give them a try. You won't regret it.