If you have proof, go to posh but also file your own case. I filed posh case against a guy who has 3 posh cases against him in the past at the same company, nothing happened because he is apparently right hand of the director. He was promoted and moved to London.
I would have dragged the companyβs ass to the court if I had proof.
Please make sure you are recording every conversation with this guy. Please collect proof.