Given it's a two-step process, it's hardly an accident. Were you bidding, or were they Buy It Nows. If auctions, then bidding on 2 identical items is definitely not an accident.

Provided you don't renege on another purchase in the next (or previous) 12 months, there are no consequences except that the seller of the item you don't want is highly unlikely to allow you to 'purchase' from them again.