Two thoughts here:
1. Seems to me that you legitimately earned the DSUs from a published promotion. Just send the terms of the promotion and # of nights in the required timeframe to WOH concierge, and your DSUs should appear once validated.
2. WOH is chaotic, to put it nicely. The change from GP to WOH started the move towards chaos, and the loss of Jeff Zidell seems to have made the organization rudderless.
If necessary, write to Mark Hoplomazian, CEO of Hyatt.