I had the same issue. Go to the virtual assistant and ask for a live agent. You should get a link that will take you to a live agent. It's open 24/7. They are escalating my case as it hasn't been resolved yet. I'm lucky I still had the email that I got 30 mins before the show that my parking passes had been cancelled. Make sure you take a screenshot if stubhub sends you a request for a refund or get other parking tickets, take a screenshot as they will probably ask you to prove you never used the parking tickets.