Drove Through About 0.5 Meter Water. Help  

O.P.
Important info:

Car – 2010 Mercedes-Benz c200 Kompressor, Petrol

What happened – Drove through about a foot deep of water on a flooded road at about 5km/h (had to the way traffic was directed) (about 2-3 seconds in the water)

When attempt to start – Nothing happens, it almost makes a quite thud noise not normal key its one of those sensor keys, might have something to do with the thud noise? (again, it’s very quiet).

Tried to manually turn engine but it didn’t work. (Yes, it was in neutral)

Car not in my position at the moment.

So, I drove it through a bit of water and only about 3 second after leaving water did the car stall, I pulled over and tried to start it nothing happened, didn’t even try to crank up.

So, I put in an insurance claim they sent it to their mechanic and shortly after they told me that it was a write off (he said the engine seized). Now I don’t know much about cars but when I went to get all of my belongings out of the car it didn’t look like he really did anything to it, as in take anything out from under the bonnet; maybe because I’m in denial but I feel like they just got in the car tried to start it looked up the engine price (they told me it was about 13K for new engine) so they wrote it off then pay be out then maybe they end up finding a fix and auction my baby and then it’s too late.

I’m going to get a second mechanic to look at it for me to make sure it isn’t something small, not sure if they have some sort of sensors or anything in them that could maybe be wet and not allowing the car to start maybe?
I am going back to talk to the guy who checked the car, what should I be asking him, and what should I be asking my second opinion mechanic so that I can be 100% sure that it is in need of a new engine and that insurance isn’t just trying to do me dirty?

Thanks for any help in advance!