Oxford will not pay what i am rightly owed

I was crashed into by a client of oxford claims. I stupidly was advised by my insurance company to go through t3rd party claims. got three quotes the lowest one was R 12 300 plus. Oxford think that is fine to not only offer me a measly R7402 they are refusing to provide me with a copy of their loss adjustor's her managers details and seh will not give them to me, she either puts down the phone or will not reply. I am disgusted