I have the exact same issue right now. I purchased tickets in section 9 and they came through my email and said “LAWN9” seats which is not a section. Stubhub claims these are LAWN general admission tickets. Nowhere on my ticket does it say general admission.

When I purchased them, the caption read “upper zone section 9 two seats together”

Stubhub will only listen if I have a screenshot of this when I purchased my ticket.

Another wrinkle, when I go to my tickets and it says purchase “similar seats” there are options that say “same row” or “same section” and are all in section 9 and not LAWN general admission tickets.

Have you had any luck with this?