I believe the store you are talking about is Costco, not Cosco...
It's amazing you got that wrong..you would have written a powerless lawsuit if you were suing "Cosco" lol
I went to a Costco in Garden Grove with my friends last year. At the entrance, the girl said they only allow 3 people go in per card and we are total 5. But she said it is OK for this time. My friends from China bought 3 full cart merchdise cost about $ 5000. I asked a employee to approve OK to use my card. But the manager yelled to my friends: We don't allow you go in but you guys used the card twice. We only allow one receipt. We refuse to issue more than one receipt. I said Costco allow one receipt with subtotal and we never want more than one receipt. Actually we paid for only one receipt already. The store manager still yelled to my friend. I told him that if he yelled one more word, we will return all the merchdise and complaint to this up level.
Also in this Garden Grove store, a different manager refused me to return a defect 52" TV with in a month. I called this store before I came. Finally I returned after I called the headquarter in the store.
In some day, If There are only few custmers a day, I believe no manager would yell to Chinese anymore just by get jealous of their purchsing power.