This is probably a silly question, but why are you listing something at less than 15% of its value or of the going price? You don't have to answer that.
To the best of my knowledge listings cannot be changed if there are bids on them. And there are also restrictions on changes in the last few hours (24?) of an auction, I suppose to protect snipe buyers who may have placed their bids with a sniping service many days before.
Snipe bidders are good for sellers, and eBay, since even if they don't actually win, they do push less confident bidders to their top bid.
You can however, cancel any bids and then end an auction at any time. If you don't cancel the bids before ending the auction, the high bidder is deemed to be the winner, so attention must be paid.
Sending a polite note to those bidders before cancelling explaining the problem would be helpful, since they might have been bidding higher than you could see and with communication may bid when your relist a clean description.
