I think there are a couple options. He can tell them to fuck off (or rather tear up those ballots), which I think would reduce the number of votes needed to win, handing it directly to Trump. He can also say “hmm, we have two sets of electors here from these states, I don’t know which to choose,” in which case the winning number would still be 270. In that case the president would be elected by the House, and the VP by the Senate.