Issues Selling Ticket - Stubhub Won't Change Delivery to Mobile Transfer

I sold a ticket to a show here in Mexico. The tickets were being sold by a smaller ticket vendor with their own platform, not Ticketmaster or another big name. The only options for me to list the tickets on SH was either e-ticket or physical ticket. I selected e-ticket because the tickets are on my phone not realizing that e-ticket to SH is a pdf ticket. There is no possible way I can transfer this ticket other than an email/phone transfer via the ticket sellers own ticket app.

I've called and chatted and emailed and my case is being "escalated" but I have no paper trail of my issue and no updates after weeks. All I need is for them to change the delivery method to mobile transfer. I don't have the buyers information so have no possible way to contact or initiate any transfer on my own. Has anyone else ran into this issue and have any advice? I'm worried they will end up charging me for a ticket I have no actual way to send.