Need some help from you travel savvy folks! I'm looking to upgrade my B class ticket on EVA.

I called EVA who said there is one upgrade seat available on that flight, but that I had to work through UA. Went to UA SAUA website, but it resulted in an error message. I called UA, but they say there is no availability, and they can't do anything.

1. Any recommendations for next steps?
2. If there truly is no upgrade available right now, will EVA release RL seats in the future? I read somewhere that they release RL seats T-14.
3. Can UA see upgrade inventory for this BR flight?