American Leak Detection

I called these folks regarding a 1.75″ per day pool leak problem and was told that they use a helium based technology that would find the problem (s). When they arrived they did a pressure test of the plumbing, which was fine. They then proceeded to jump in the pool and swim around with food coloring visually looking for leaks. I expressed concern three times and explained that I was told that a technology solution would be used. The technicians, who in fairness were really nice guys, said that the helium technology was not effective and that the manual/​visual method would find the problems. They did find about a dozen holes and patched them. Over the next few weeks I noticed that I was still losing about .75″ per day. I emailed American Leak Detection to see if they warranty their work.
Their email response was that they checked the pluming, patched 10 – 12 holes and told me to buy a new liner ($ 4,000).
The technician actually told me that I was good to go for the season but would need a new liner (probably next year).
In summary, $ 400 spent for these folks to find a bit more than half of my problem. A very disappointing and expensive contractor solution on my part. I will now have to find someone who can do the same work and hopefully find all of the holes. I have heard that there are very capable companies with solid detection equipment. I guess I just need to be more careful next time in confirming (up front) exactly what I am paying for.