Accidentally redeemed same movie twice on iTunes

[jbloggs]

I accidentally redeemed same movie twice on iTunes since I didn't realize I already had it my library. I called iTunes support and they basically said there is no way to "unredeem" or cancel the redemption so that the code can be reactivated. I even spoke to the senior support supervisor who said the same thing. They were also baffled by how I have many 'free' movies in my account and asked where I got them from. I explained to them that when you purchase certain blu-ray/DVD movies at a store, they come with free digital copy of the movie. OMG these are the 'genius' of Apple. Why do they even allow a code to be redeemed for an item that is already in the library

I know people have post about this before and have successfully managed to get the second code removed from iTunes and recover the code to be used elsewhere, so was wondering how to best go about doing that and who exactly should I contact?