I have several dell promo gift cards from a large purchase that I recently attempted to use but was shocked to find that they were all showing as invalid. I have attempted multiple times to call Dell Customer Support to no avail. My next step is to call an agency to file complaints against Dell.
I had the same issue for both promo GC and Regular GC. This seems to be a common issue and DELL needs to take some actions on it.
Thanks for posting.
Information about the promotional gift cards and how to contact the Gift Card department is available here: http://dell.to/2hPVAZy