If the pony was re-listed as BIN, she may have sold already. However, it seems likely that the seller had pulled the auction. Maybe s/he thought the pony wouldn't sell and decided to keep her or sell through another channel, or even donate to charity? I have also seen some auctions where a good seller has listed a pony then noticed a flaw and took the listing down to re-list at a cheaper price, then I have also seen bad sellers re-list for a higher price...
Its hard to say for sure, but it is very likely that the seller took the pony off for some reason.