Mechanic Shop Caused 10k Of Damage To Car And Is Denying Claim. What Are The Next Legal Steps?

TLDR: Went in for routine oil change, came out with an undrivable car that needs 10K worth of work and a new transmission. Trying to figure out what likely happened and what to do.

Here’s the story: I dropped my car (2017 Subaru Impreza) off Shop A for a routine oil change and tire rotation. They performed both, called me and told me that they did an inspection and that everything was great EXCEPT that my car was “making a noise” and that I was low on power steering fluid, which I would need to have checked out by a dealership. I told them that I have an electric system and that I don’t have power steering fluid. They brushed the comment off and told me to come get my car.

As soon as I pick my car up, I notice a new whirring noise and that the car was severely shuddering when I drove. I drove it a very short distance before turning around and taking it back to Shop A, where I informed them of my concerns. A mechanic first brushed it off, but I insisted there was a problem. The mechanic got in my car, drove it around the lot, and immediately pulled it into the service garage. At this point, he told me I had “no transmission fluid” and that they would add a bit for free. They said they didn’t have the correct pump system, so they added it with a hand sanitizer bottle pump (literally).

I asked the manager of Shop A if they inspected the transmission fluid during the inspection they supposedly performed and he said no. I told him that it was unlikely that I had no transmission fluid because I had just gotten a state inspection less than 6 months and 2,000 miles ago, where they said my fluid levels were fine and that the fluid itself did not need replacing.

The mechanic kept adding some fluid, brought my car down, and told me to “bring it back tomorrow so they could double-check everything.” They did not allow me to leave my car in their lot, so I drove it home (a very short distance) where the same issues were still present.

The next day, I turned my car on, noticed how intense the whirring noise was, and decided it was not safe to drive. My partner and I called the shop (which vehemently denied any responsibility). We got it towed to Shop B for a damage assessment. They found that the CVT was entirely shot and would need replacing, the oil gasket was missing, and an incorrect fluid had been added to my car. Shop B suggested that the transmission fluid may have been accidentally drained during my service at Shop A, then it wasn’t replaced, and then some fluid damaged the CVT pump to the point of the system needing total replacement. The damage is over $10,000.

That takes us to now: I’ve gone back and forth with the shop’s insurance but just had my claim denied because I can’t prove that they are responsible. I’ve submitted every document, photos of the transmission fluid Shop A added (my fluid should be a bright green and the one Shop B drained from my car is a dark brown), evidence of a recent inspection where the fluid was fine, and Shop B’s assessment that Shop A caused the damage. My question is: what kind of lawyer would I need to work with to address this case? Is there even a compelling case here (I think so and Shop B thinks so, but we’re not lawyers). I wanted to avoid suing, but I don’t know what other options I have left at this point.

TIA — anything helps.