I had found the old tickets in my "expired passes" part of Google Pay up until a day or two before and then they just disappeared on me. When I tried to re-download them to Google Pay from the VT sports app, it wouldn't let me because those tickets had already been downloaded.

If you can't find your tickets, you should be able to go into your VT ticket online account and "reissue" your tickets. When do that, they send you an email with your reissued tickets and you can then print them at home. That's what I ended up doing, and we had no problems getting into the game.