Angry Client

We took our car to bosch to have it checked out due to some abnormal signs we were experiencing,however we were told that the car had a turbo problem,they did a quote then send it to Lombard insurance,they stripped the car and check it.Now we are being to that they won't pay the repair as the damage was caused by a blockage,the same car which has a service history from bmw and would go for another service by the end of this month.We took this extended warranty for such things,however we find ourselves in this position,then what is the use of having such a cover if it won't help us.At this points and time I want out money back and we will go pay for it to be fixed because clearly we have been paying for nothing.