Personally (going on my past staff experience) that's the fault of the other user and I wouldn't deem it necessary to punish you for not completing it, considering as well of course that item duels aren't enforced as strictly as actually trading. However the decent thing to do would be to settle it in another form, for example, an equal amount of TC or an alternative item of equal value.
Please don't take this as an official statement, although I used to handle scams etc I've been out for while and I think this could come down to how the chosen moderator chooses to deal with it. In any case it isn't fair to punish you because you physically cannot send an item.