A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 102,617
My guess is that DL failed to reissue your ticket after confirming the RUC upgrade; it could be in the reissue queue. Did you get an emailed receipt with a new ticket number after the upgrade?
Call DL and have them fix this now. You don't want to risk missing the flight when airport agents try to fix the problem.