Third Party Liability Claim Refuted by Outsurance

I was in involved in a car accident with an outsurance client on the 20/06/2018. Outsurance bumped my car from behind. The outsurance claim subsequently sent me the claim number to do a third party claim. On the 23/06/2018 I contacted outsurance third party liability department and inquired on what I need to send in order for my claim to be processed and finalize and they subsequently sent me the liability claim form that needs to be submitted with all the supporting documents including quotes for repairing my car. I send my claim form on the 28/06/2018 with all the supporting documents and I received and email from ********** confirming receipt of my form with all the supporting documents. On the 29/06/2018 I received an email from ********** informing that my claim has been Refute on basis that I am the one who caused and accident and there was nothing that could do. She the basis of refuting my claim was because her client statement was correct and I won’t assess my statement. I am not satisfied with results of the claim. Outsurance liability department are so unprofessional and never want to listen to my side of the story. How can I be the cause of the accident because their client bumped from the back. Claim Number: ********** 7 Outsurance Consultant; Anina William.