I have a similar experience with a CGC comic. Long story short, I wanted to pay for it after purchasing another item so as to save on shipping. But after numerous attempts he still didn't combine the purchase and send the invoice. He told me he sold it off to the second highest bidder and cook up some lame excuse. A few days later he listed it again. I gave a bad feedback and reported the item. Both to no avail. I think as long as you didn't pay for it, the feedback can be removed. Btw the item went for much higher after that. But I do hope yours is not the case.