Any issue that is remotely complex and requires specialized attention like yours, Stubhub will just do nothing on. I have an issue where I purchased tickets from Stubhub and they were delivered to me by screenshot. But, these tickets were the EXACT same row, seats and section that I had bought myself from Ticketmaster for the same event. Obviously the ticketmaster ones have to be real and the Stubhub ones fake.
They have been "escalating" this case over and over again for 7.5 weeks. (That's not an exaggeration), refuse to refund me, and every escalation leads to nothing. I've been promised five different dates they would get back to me by and I haven't heard back from Stubhub one time. I've been spending 1-2 hours on the phone with them weekly.
I truly think that part of their business model is to exhaust customers who need customer service so they stop calling and Stubhub can just keep the money.
Anyway, its horrible but its very unlikely that they will ever do anything about your case (or mine).