Contact higher up, and let them know you will no longer purchase from them, and will be contacting the manufacturer as well, so the manufacturer knows what kind of disty they have.

I don't care if the disty opened the box to inspect it, took the item out to see how it works, or sat it on a table for a non powered demo. Once that box is opened, it is not a new product, and must be sold as B stock.

End of story.