Stock & size

I've been running with Asics Cumulus 12 for 7 months. Time for new running shoes. Did my research, either Adidas Adios Adezero or Nike Pegasus. Nothing in stock for US11. ALMOST NO STOCK IN US11 WITH ALL SHOES. I go for the Asics Cumulus on sale, since they served me well previously. Didn't have to fit, I ran over 800km with my previous pair. The first run was uncomfortable. New shoes, so I try again. Not better. After my third run I only see that they gave me the wrong size!!!! I repeatedly said I'm looking for US11! They were on sale, so no box. I tried them for 3 runs, so they have some dust. So now I have a brand new pair of useless shoes. Don't even want to deal with the staff at that store. They lack stock and common sense, like giving me advice on my running style. What can I do??