So sorry to hear about your experience. The cancellation policy can be great but the T&C don't specify the time zone in which "midnight the next day" applies (
here). If I am in a west coast city booking travel that begins in Florida does midnight refer to Eastern time zone or Pacific? Could this be a factor?
FYI, your age should never have anything to do with how you are treated either by DL or here on FlyerTalk. Money is the same shade of green no matter how green you are.
Wish I had more to offer. FYI, for the future, there are many easy and cheap ways to extend the expiration of your miles. Every one of us on this board groans like a man watching a baseball player get beaned when we hear of 35K miles expiring. A tip: if you have a free (or even a $ one) email account with any of the big email services (yahoo, gmail, etc) you also have a calendar on which you can place appointments and what-not. They also let you set up reminders that will be emailed to you at a designated time you specify prior to a special date. I have misc miles/points in several accounts and I have myself emailed when the expiration date is drawing near. Each mile or point forum (for programs where expiration is an issue) will have threads pertaining to keeping expiration from causing you to groan. The DL one is:
The Definitive “Expiring SkyMiles” Thread.