Toyota - Damaged clutch in car

My car has a wired clutch system and back in February, there was some noise being produced on depressing the clutch. After wasting * days of to and fro, regarding the fix the service manager assured me that he would ensure proper fix for the same. My car was sent to Uttam Toyota (sector **) and I was told that the head technician would be deployed to check and fix the issue. They managed to get rid of the noise by lubricating but then, they reported that my clutch was "slipping". I was not convinced because I knew that the same problem was not there previously (it is my own car and I am the sole driver) but they insisted on saying that it may happen due to driving habits. I went to another Toyota dealership in Noida to inspect the same and get it fixed. When the clutch cover was opened, it was found that there was oil in there. It was apparent that due to the oil, the clutch slippage took place. Hence, this easily meant that Uttam Toyota's lubrication policy caused more damage than fix. The same day, I reached Uttam Toyota Sector ** to show the service manager the replaced part but he clearly denied his team's mistake.