Data Point:
-refund requested on May 9th (CC & DL GC)
-still pending as of today (Sept 13th).
Messaged DL this morning to inquire and was told that due to a gift card being involved my request has to go to a "specifically trained refund specialist" and the rep could not or would not give me an ETA on when to expect it to be processed.
See my DP from September 8th:
(FWIW, I'm a DL Diamond and 2MMiler)
DP:
Today - after more than 5 months - I received a Delta E-Certificate for the amount paid with Delta Gift Cards.
Three more to go .....