Poor Customer Service

My vehicle windscreen was damaged due to a stone from a truck, Discovery Insure is refusing to replace the windscreen with an original, they want to use an alternative brand, from my understanding of insurance, insurance is meant to put you in a same position you were in previous to the incident. I have contacted them and they indicate that is their policy, clearly it does not state this in their policy I received. I was contacted by a Supervisor "Azime" refused to give me her full name, indicating they cannot assist the vehicle is a 2012 model and its their procedure. My vehicle is original from back to front in pristine condition if I wanted an alternative brand installed in my car I would go to a ***** workshop and have it done. Never had this problem with Dial Direct, they were more expensive but way better customer service. Will be sending this matter to the Insurance Ombudsman and thereafter cancel my policy with discovery including my RA and Life Insurance.