The same thing just happened to us when we came the end of September. We phoned home and got my father to give us the numbers off of the tickets and then had to go to guest services at Magic Kingdom. The concierge at our resort (POR) said they couldn't do it that we had to go to the MK. They replaced them with no problem, I just needed ID (as the tickets were mailed out in my name) and the numbers off of the tickets
We forgot ours in our hotel room and didn't want to go back for them. We went to will call and they were happy to replace them for us, no confirmation numbers needed. All they required was the I.D. of my DH who purchased the tickets.