Brand new Kodiak trailer - can't use toilet

So there is also no support under the tank so it's going to form a sagging belly when full. Next thing you know it will be cracking the drain fitting where it goes through the frame work. Sorry to hear of all the heck you are going through. I have told DW several times that if we had bought a $40,000 new one and had a ton of trouble I wouldn't be able to handle the stress of it all. Hope it works out for you.