Listen, speaking as someone who has been involved in lawsuits (intimately) over issues of negligence, I laugh at the notion of suing over what you're describing.
You have no clue about how much time, work and money it costs to sue someone. (I do, first hand.). It would be cheaper and easier and quicker and less pain for you just to get your car fixed. Trust me on that.
I don't know what type of car you drive and how the lines to the gas tank are set up. Usually there are 2 hoses that run from the tank to the filler. One takes the gasoline from the pump to the tank. The other is a vent and you can usually see the orifice at the fueling door. From the fuel tank there is the line that carries the fuel from the submerged fuel pump to the engine. There is the fuel return line which carries unused fuel back to the tank and there is a line that runs to the charcoal canister which is part of the evaporative system. But usually in the tank there is a check valve that prevents s you from over filling your tank. This could be as simple as a ping pong ball that floats in the gas and as the fuel rises during fueling will be pushed into the outlet of the fuel filling pipe blocking the introduction of any more gasoline once the fuel tank is full. The fuel that shot out of the filler neck was or should have been just excess fuel collected in the filling line.
It is not unusual for excess fuel to shoot out of the filler. I've had it happen many times over the years. Never had a problem like you're describing other than some gasoline on my shoes. I've also had the problem of the fuel pump shutting off prematurely repeatedly.
If your charcoal canister is flooded, it might dry out on its own. At worst you would need to disconnect it and pour out the excess fuel. (But I'm still not sure that's your problem.). Or a new canister. Either way, less grief than suing some gas station.
