I just got level 50 and completed the North Vern quest chain with a character Kayostheory on the US East Server Avesta and I have not received any Powerpass in the mail.
Hello @msellisonii , welcome to our forums!
I’m sorry to hear about this issue with your game, before we start working on a solution I wanna know if you have done any sort of troubleshooting so I can take that into consideration?
I’ll be waiting!
not sure what kind of troubleshooting I can do, I leveled a new character on a server I also created a couple of Alts, I got to level 50, completed the North Vern quest line, got item level to the required.
Sorry for the late response, I have a question, have you received another powerpass before on that region?
yes, is it region bound?
Hello @msellisonii, I apologize for the very late response! 
To answer your question in case it still stands, yes, power passes are region bound, you can get a max of 2 per region.
Let me know if you still have any other question!