In-game customer support is a subscriber-only feature (and as bogged down as they get with just subscribers, yikes). The Defiance mission not being completeable is a known bug, that I believe is being worked on, though Talos being missing seems to be a new wrinkle on another known bug with missing companions in general (Torian is the most usual suspect there, it seems).
So long story short, these are known bugs that they are working on (anyone responding to you in these forums are fellow players unless their username says EA_ at the front, so we are volunteers and don't reperesent either company), but they have not given us an eta on completion (or not one that I have seen).
