You cannot retract a bid if the auction is over and you are the high bidder. Is the auction over?
"if the auction is over, you're obligated, but if you don't want it, don't pay... what's he gonna do? Give you bad feedback? Oh no.... just tell him to repost it."
Not necessarily true. If you won the auction and do not pay for it (assuming he does not let you off the hook) then he can leave you negative feedback AND he can file a non-paying bidder's report to Ebay. If you get three of these you can be perm kicked.
BTW how much are you on the line for ($)?