Dude it's the classic trick. They make you wait a long time, then when it finally gets delivered to you and there is minor damage they rather knock off a couple of bucks, because they know your not going to wait another two weeks for the truck to get back into town. Plus I bet there is a re-shelf fee if you reject the tank for chips. But in this case the chip was on the bottom of the tank and can be easily hidden. Now as for the seal job on the inside I agree with everyone else it be in your best interest to place water in the tank and let it sit over night in the porch. When I did heavy aircraft maintenance there were lots of shady guys who used sealant to there advantage and would place more than need to hide a hacked up sheetmetal job. Besides it will just strengthen your case if they go to talk trash when you return there product.