Pool installed in 2004 failure in 2015 caused by improper main drain installation

We bought the house in 2008 with an inground vinyl pool. I noticed that around the main drain a dip had occurred. When the very pool company that installed the pool in 04 came to close the pool for winter I showed them the situation with the main drain and they said it was perfectly fine. When I went to open the pool this year 2015 the water was way down. I suspected it was due to the main drain and went to the company had them come out and look at the problem. Their recommendation was to hire a diver and patch the leak stating that the main drain was fine. Since a diver, buying a truck load of water, and repairing a supposed leak would have cost $700 I opted to replace the liner due to it's age and suspecting the main drain was the problem. Once the old liner was removed and the main drain inspected the problem was caused by improper installation of the main drain. The two gaskets were missing from the main drain causing a leak which washed away the dirt under the vermiculite causing a collapse which in turn made the leak worse. Also the company had not put any concrete around the main drain for support. If the gaskets had been installed in the drain the leak would have not happened. So failure to install two 75 cent gaskets in 2004 caused a pool failure requiring a $6000 + repair in 2015.

A legal action in this case is most likely not possible due to the time that has passed. However I can post photos and tell this story on Angie's List and other such sites to make sure this company is brought to task in the court of public opinion!