At first I was wondering what you were referrng to. You need to post eBay links or auction pictures.
Below are two Shmoo auctions, one from July and one from May of 2015, but neither was a Buy it Now. I found them in my bookmarks, but not in an eBay search of completed auctions. I don't think it illustrates a trend because it's just two phones. The completed Contour , also shown below, that brought over $2,000 means those phones are not going that low.