Navy blue duvet cover set, queen size

I lost my navy blue duvet cover set yesterday around 3pm. It's a queen size, soft cotton sateen with a zipper closure. It has a small white monogram 'A.J.' in the lower-right corner and a faint coffee stain along the inner seam—nothing huge, just enough to spot it when you unfold it. I last had it in my apartment on 2nd Ave N in downtown Bismarck after I finished laundry and stepped out briefly near the State Capitol on Memorial Highway. It really mattered to me because it was a gift from my grandmother, and I’d really appreciate getting it back.