Sewage smell from last week's storm

We had a bad storm in New York last week and my car was slightly underwater but not above the engine line. Still the sewers gave up and stuff came through the popped manholes and it was disgustingly smelly.



Upon driving it away it appeared we were burning sewage which made the car stink to high heaven.



The dealer whom I desperately drove it to claimed they scraped off whatever they could and ran it through the car wash 10 times and ran the car for 3 hours to burn off the rest of the stuff.



The car still stinks and they suggested taking it to a place which can do undercarriage pressure wash.



I need help - is this car gone! Will I ever get rid of the smell?



Joe