Thanks Philibo.

I have realized that these guys have done very poor job. I have some more problems:
1. The pipe that they cut to do pressure test, is leaking when I run the pump.
2. The bottom (main) drain cover they took off to do pressure test, comes out whenever there is a water movement (except when the pump is running) at the bottom of the pool.

After having a lot of thought and talking to other pool material merchant I have decided to dispute the charge.

Once again, Thanks for your advise.