You must have needed a TT in a hurry, as you posted.
If the dealer has any ethic at all, he should settle up with you on the damage discovered like the floor and tank.
If it was me, I'd be getting a pressurized leak test done to discover if there are other issues like the roof or walls having leaks. I do the pressure test using a furnace blower, directing the air in through a window and spraying all over the exterior with a spray bottle of soapy water. I've seen where other guys use a leaf blower or a commercial fan, anything that moves a lot of air will do the trick.
Here's a leak I discovered when doing the test:
Don't beat yourself up too bad, we all get in a hurry and miss something now and again. Doesn't make you dumb, just a guy trying to get along. I'd keep on the dealer and salesman until you get some settlement.