Bad Service, ******* Warranties via AA (Advantage Motor Protector)

Shocking almost bordering on being ***** .They are refusing to pay for my repairs .They say they would have have paid if the turbo was broken .The car was losing power and with lots of smoke at certain periods and fixing or attending to the matter earlier lessens the serious damage that could happen to the parts of the car if not attended to.The Specialist report says the same and they say I should have waited to get stuck and have more damages to the car .This is ridiculous and wanting to rip me off after paying them for nearly 2yrs with no claim.