Be very careful with weird activities of bid retractions on the items! Why? In some cases (probably more often than one may think of) these things can be abusive against the seller. Some buyers manipulate with them to find the current amount of highbid, or what is worse to drop the final price at the end of auction. Therefor eBay has blocked the retraction of bid option within the last 12 hours of listing, but still such price-drops may be harmful to seller even during the last day of auction. Be also careful if the bighbidder or (especially!) 2nd bidder asks You as a seller to cancel his bid.