Audi Central Houston

I have been bringing my Q5 into this dealership for several years for service. In June 2017 I brought it in for a camshaft issue and was told that the entire engine was basically removed and reinstalled to facilitate repairs. This was all covered under my CPO warranty. In November of the same year I brought it back to this dealer for a possible oil leak as the cover at the bottom of the engine was filled with oil which pointed to a possible leak. I was told that the cleanup that occurred during the major repair in June was poor and that the oil we observed was left over from that repair. The service department cleaned it up and assured me there was no issue. Then in July 2018 I brought it back in because the low oil pressure light came on and would not shut off. I had it towed in at the dealership’s recommendation. Upon inspection the service department told me that the light was on due to the oil filter needing to be changed. They changed it out, charged me $200 for the “oil change” and sent me on my way. Then, last week, on July 3, the oil pressure light came on while braking. The light was only on for a moment and immediately turned off. A few minutes later the check engine light came on and stayed on. The same day, I received an email from Audi stating there was yet another recall on my car and I needed to schedule service for it to be repaired. I clicked the link in the email and set up a service for the recall, an oil change, along with a request for the low oil pressure and check engine lights to be diagnosed. I brought the car in on Monday, July 8. I was told at that time that my warranty expired in October (which I was unaware was due to expire; I was under the impression I had a warranty to 100,000 miles) and I was basically on the hook for any repairs. Then yesterday I received the repair estimate for over $4000 for an oil leak. I have been bringing my car to Audi Central Houston for 2 years for a possible oil leak and low oil pressure light illuminating on my dash. I have been told each time that there is no problem and sent on my way. How is this possible that now that the warranty has expired the oil leak has been confirmed? The problem started during the warranty period but the service department failed to diagnose properly. I am frustrated beyond belief as it appears that the service department is at fault here. I have done my due diligence by bringing the issue to the dealer for repair during the warranty period. I am having a hard time understanding how this diagnosis did not come up until now, and Audi Central Houston is claiming they are no longer responsible for the repairs due to the warranty expiring. I have reached out to the Service Department Manager and the General Manager with no response.