What is the mechanical breakdown warranty policy covering

I was drawn to take the mechanical breakdown policy with AA Warranties under the impression that as long as I service my car regularly with an authorised service provider I can claim for my car to be repaired without a hussle. On two occasions since I qualified to claim, my claims were rejected for reasons of the claim regarded minor and damage caused by wear and tear respectively. The rejection decision was made despite the fact that my vehicle has been regularly serviced by a licenced service provider. My experience with AA Warranties Insurer has left me with one big question. WHAT IS THE INSURANCE COVERING? the mileage of my vehicle is within the limitation provided, the model date is within the limit provided and also the car servicing is done regularly and according to the standard provided. When I took the policy the rejection reasons were not read to me on the phone to avoid the disappointment I am facing today.