diamond car insurance

I was involved in an accident with another Diamond insured driver and Diamond assigned responsibility to the other driver, it took them over six months to sort out the claim and that was only after threats of possible legal action from myself. I have spent hours on the phone trying to move things along and am always promised something will be done but it never is. When i call back i can never speak to the same person, and the call centre staff vary from polite but not much help to rude and arrog ...