I recently started selling some cards on Ebay. Today after an auction ends, the winning bidder sends me an email asking me to "take his bid off" because it turns out "it's night the right card and can't afford it." I tried to retract his bid, but was told that I can't do that once the auction has ended. I sent a second chance offer to the next highest bidder. If accepted, will this void the original listing? Are there any other actions I can take?