Worst Insurance company

I made a third party claim with one insurance and for 2 months they have been dragging their feet! Their client wronged me (wanted to overtake and bumped my brand new car) I sent all the documents they needed from me, now they said they will only settle 70% of the claims and the rest I have to pay myself. After going around getting quotes,making countless follow ups with them via email, phone calls they still do not take you serious.