A similar thing happened to me as a seller. I saw that one of my old textbooks was selling for a nice price, so I listed it along with two other used copies. I priced it $1 cheaper than the lowest price offered, but within an hour both sellers had changed their prices to $.01 and $.02 cheaper than mine. I reduced it two times more by $1, and each time they beat my price by a cent or two. So what I did was reduce my price by a few dollars every hour for one day until everybody was priced under $5. Then I bought their books and changed my price back.