Auto&General Neglegence

Hi, I recently cancelled my policy with Auto & General mechanical warrantee cover due to their lack of assistance with regards to my claim. I took an extended warrantee on my audi TDI 3dr and upon the request I did ask the consultant relative questions with regards to what specifically is covered under this policy, my car being a 2012 model I worried over wear and tear, my engine type was not specifically underlined so my understanding was as per the policy the engine and any mechanical breakdown would be covered. I recently had a breakdown whereby upon diagnostics the mechanic at the workshop highlighted an issue with the diesel particulate filter as well as the catalytic converter. He suggested that a regeneration process will rectify the issue and as such he will process the claim with my insurer (Auto&General). He informed me that he sent through the diagnostic as well as the quotation however the claim was rejected, I was told this by the mechanic and not Auto&General. This is poor administration from Auto&General as I feel that as a paying client I was not informed by them why the claim was rejected, furthermore the specifics of my engine type were concluded as if it is any other vehicle, absent of the fact that it has specific components and as such this was not communicated. I was give no feedback from the insurer, also I have a contract with them not the mechanic and demand a formal rejection letter as well as the assessment report