Welcome to Flyertalk! I'm going to move this to the Delta forum, where you're likely to get better answers. Before I do that, I will note that the
travel exceptions policy indicates refunds will be given, but I can only see the travel agency refund reimbursement form. Presuming you purchased your ticket directly from Delta, you should consider calling back and referencing this policy.
chgoeditor
co-mod, Info Desk