I'm so sorry to hear about your bad experience!
Most of the SA's at the Honolulu Dior boutique where I shop, are so nice! Although I have my regular SA (she is the absolute nicest one ever!), the others will come by when I am in the store just to chat or to tell me that its nice to see me again. Part of the reason why I continually buy from this brand is because of the excellent service before, during, and after I purchase an item. Its been that way since the very first time I walked into Dior and primarily browsed the sale. I understand what you mean about rude service though. There is one SA there who will only acknowledge Japanese tourists as they tend to spend a lot of money at once. She was snooty to me one day when my regular SA wasn't there and I asked her for a price on something that wasn't marked. Since she gave me attitude, I made my purchase through another SA who was so warm and sincere. He even offered to ring my purchase up through my regular SA's number so that she would get credit for the sale (of course I told him that wasn't necessary). I also received horrible service at LV and Chanel and on a day that I went in specifically to buy a new bag.
Gucci is hit and miss and Neiman's is usually okay since we're in there so often! LOL!
Do send a letter or an email to the district manager with as many details as possible. I agree that most luxury type establishments will take the matter very seriously. Again, so sorry to hear about this.

Come shop at the Dior in Honolulu and you can visit my SA who would totally change your mind about Dior's customer service!

Hope your next visit is much more pleasant! The bags are way too gorgeous to stay away from just because of a few rude people. After all, aren't they the ones working while we are out leisurely shopping? And how would they earn any money if we didn't spend ours? They should be grateful for any business. Without their clients, they wouldn't have a job...