Quick question: can I trace/track my delayed baggage online via UA website when they have transferred the bag to a Delta flight for rerouting?

I flew UA IND-ORD-AUA (no weather delay, full fare ticket, pd $25 bag fee) on Sunday but as of Tuesday morning no sign of bag. Online tracking says UA sent bag to Delta on Monday, rerouting it ORD-ATL-AUA for Monday arrival. Assume it was arbitrarily chosen to not get loaded in ORD on Sunday as similar bag with flying companion arrived with no complications. Can anyone advise me on what I can spend with reasonable assurance UA will reimburse? I've avoided UA since merger and feeling no love yet as I wear the same winter jeans for 3rd day of 7 day beach vacation/wedding anniversary. Grr.