Best Utility Line Location in New York NY

We had American Leak Detection come at the recommendation of a plumbing co. They came to locate a leak causing a high water bill. They found no leak except a drip in a faucet. The water biter calling the county ll remained high, which I could not see until the next billing period. After calling the county water co, and them saying I MUST have a leak, I called this co. They did not return calls and when I finally got in touch with them, they refused to come back without the full $450 charge and when I asked to have the boss call, no one ever responded. ACsaid he didn't want to get the boss annoyed, and I responded that I guess he thought it was better to have an annoyed customer. And no one responded.