I'm in a similar position, I started the process on the 5th of August and it took emailing/calling several times before getting feedback my documents weren't accepted on the 17th of August.
I had to keep resubmitting until they finally accepted the format on the 21st. Since then there's been zero progress for all the senior advisors my case has been escalated to.
All I get is apologies and people saying my case is being looked at with no ETA in site.
I've given up at this point, Apple have basically frozen my account, I can't update my app or release anything to the app store because my team ID has been floating in the void since starting this process.
Its really made me consider finding ways to deliver applications/services without having Apple as my only platform because from the app approval process, to opening and now upgrading my app its been a terrible show and just a massive headache.