The forces arrayed against you are too great, and likely driven by financial and political considerations. Best get another job, or keep your head down. I have

The forces arrayed against you are too great, and likely driven by financial and political considerations. Best get another job, or keep your head down. I have worked in large orgs where senior managers have taken back handers from vendors. I've even seen someone dismissed for that reason. My guess is there's shady stuff going on several levels up, and it will only hurt you if you try to fix it.