Water Meter still Showing Usage, Possibly a Leak

Hey guys, so yesterday morning my mom received an alert from Aramark that there is a possible leak that started on Sunday night as it states 2 gallons per hour of water usage.

We live in the county in zip code 77082. They came to check it out and explained that on their side it doesn't show an issue.

We have checked all the faucets (inside and out) and toilets, sinks etc and it's still showing usage on the meter even after turning off the main valve. Turned it off last night and checked this morning.

I know we will have to call a plumber but we're worried about getting scammed/overcharged. Any recommendations?

Anyone have ran into a similar situation and figured out what it might be?

Thank you in advance.