Insure/Roadside assistance damanged my vehicle

Do not insure with these guys. Poor service from Discovery. The called roadside assistance to jumpstart my vehicle, who in turn used a truck battery (voltage too high) to jumpstart the car, which damaged it. I submitted formal complaint but no proper response and they keep referring me to the roadside assistance company. As far as I am concerned I only face Discovery so they should be taking responsibility for the problem and deal with the roadside assistance company in their own time.