Shortfall claim unsatisfactory l.

What is the use of the shortfall. I was paying my premium and had other policies for the car. My car was a write off and the insurance paid but not the whole amount. I thought since I have the shortfall insurance they will pay, but little did I know that I was the one who is going to pay the difference myself. The only thing they paid was the loyalty bonus. They sent me the calculation which included the other policy I had with other companies, and they are telling me that with them my shortfall is a negative. But the policy amount they included I was paying for the other companies and what about the amount just for the shortfall I was paying to them for a time like this! What was that for then? Was it for them just to make calculations and claim the refunds from the other policies I had with the other companies? I might as well just cancel the one I have with this other car because I don't see the purpose for it.