You might be stuck, but I'd call the AOPA Legal Services and ask
around. If you honestly saw some violations of FAR, you should report
them. This is a tricky subject. What if you were flying as a captain
and didn't want to fly a leg due to weather or any other issue, but
dispatch insisted the flight was safe. You are PIC, but they pay your
check. I am sure many people have died flying because of pressures
from the employer. You made the right choice.