scammed by restoration company and plumbers?

on 12/24 my bathtub stopped draining and my toilet wouldn't flush. In a panic I called a rooter company. Before even sending a camera down the pipes or even a snake they called a disaster restoration company. The restoration company started taking a bunch of readings and then had 3 large fan things brought in. They set up 2. After 2 days I called to have them taken away as I was leaving town on the 28th. They did not show up. I called again the next day and they came at the very end of the day. The plumbers tell me I have a sewer pipe issue and it will cost 18,000 to fix and I need to pay half up front. I write a check. Not only that, but they would have to tear up the walls and the floors in 2 bathrooms and a bedroom. The restoration company then went and called MY Insurance company and opened a claim.The next morning I called the bank and had the check cancelled. I knew it wasn't right. I left Tucson and over a week later I get a call from the restoration company to pay them almost 1600$. Since I was in the middle of a remodel on a house in Los Angeles I wrongly assumed it was for the mold removal I had just done there. I paid via Zelle. I get the first and only invoice on 1/14 over 2 weeks after service and there's a bunch of charges, including 4 machines in use and it has pictures of a Protimeter reading a 999, the max possible reading. This is in a bedroom, non-adjacent to the bathroom that has linoleum glued to a concrete slab. No glue failure, no bubbling, no warping, no mold, no indication whatsoever that water had been present. Upon returning to Tucson I brought in a plumber who discovered I only had a clogged drain. Mind you, the rooter company never showed me or gave me results from the camera test. I decided to tell the restoration company that they were not transparent, they did not tell me what the machines would cost, ( I was gone 6 weeks no one showered, flushed, or turned on a sink while I was gone. They knew I was leaving for weeks. ) They lied about the time I had the machines, they did not pick them up when I asked them to, they charged me for 3 hours of work when the other guys literally came in plugged in machines and left ...20 min tops. Removal took even less time....I threatened to take them to small claims court and began filling out the necessary paperwork. When I called them to ask for the name of their statutory agent I was put on hold for a long while. When they came back on the phone,miraculously The end up with wanting to charge me only 400$ and said they would Zelle the rest.

I became even more suspicious...I started to look at the meter readings and numbers more carefully. I looked everything up online and I am 100% convinced this is a scam that they pull, in cahoots with the rooter company to take advantage of people during an emergency. After looking everything up I wrote them an email telling them that no, I will not pay even 400$ and I would pay only 213$ for the service call and if they don't like it, I will go ahead and file the court paperwork. Before I actually send in the forms, I want to ask someone who knows more than I do whether or not the meter readings could possibly be real. This was a surface test, no pins. There is and never has been any sign of moisture. they also sent me an infrared photo which as I understand does not show actual moisture but varying degrees of heat. the reading was 17.2. Am I correct that this is celsius and means 63 degrees at the coldest part or does that number mean something else? If it is degrees, and the home itself is 69 degrees wouldn't that be a very slight difference? I need better answers than I can find on Google. And, should I sue them or let them keep 400$ of the 1600$ I paid them? I may sound petty over less than 200$ but it's the principle that matters. And I want to watch them squirm awhile.