Search:

You know what? I let my seitan sit for a long long while. Also, to increase firmness, I start with CHILLED water, put the seitan in, and bring it all to a boil. Start at CHILLED, end at boiling. That...

yep. boil, then fry.

You seem to be using raw seitan.
it needs to be boiled in a rich broth for 3hrs+, then sliced, then cooked. Mine comes out fantastics.